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Li X, Zhou X, Yang J, Böker KO, Schilling AF, Lehmann W. Evaluating femoral head collapse risk post-fixation removal: a finite element analysis. Front Bioeng Biotechnol 2025; 13:1441026. [PMID: 40114849 PMCID: PMC11922834 DOI: 10.3389/fbioe.2025.1441026] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2024] [Accepted: 02/03/2025] [Indexed: 03/22/2025] Open
Abstract
Background Femoral neck fractures are prevalent in orthopedic injuries, often leading to complications such as nonunion and osteonecrosis of the femoral head (ONFH). Studies indicate that after healing and removal of internal fixation devices, some patients develop ONFH, while others experience osteosclerosis around the screw holes due to prolonged fixation, increasing ONFH risk. Despite such observations, biomechanical studies on this phenomenon are limited. This study assesses the risk of femoral head collapse post-internal fixation device removal and investigates the biomechanical effects of bone grafting at screw removal sites. Methods Using CT data, femoral anatomy was reconstructed. For control, the femoral head's collapse area was identified. Experimental models, divided into those with and without bone grafts in screw holes, incorporated three fixation techniques, namely, triple cannulated screws (3CS), dynamic hip screws with cannulated screws (DHS+CS), and the femoral neck system (FNS), further subclassified into normal and sclerotic screw-hole models. Stress distribution, stress values, stress index, and strain range were assessed. Results In both models, DHS+CS showed the highest stress in the overall model, while 3CS had the highest stress in the collapse area. The 3CS configuration also resulted in the largest strain range, which was observed in the central pillar of normal screw-hole models and the lateral pillar of sclerotic screw-hole models. The bone graft models exhibited lower peak, average stress, and strain values than the normal and sclerotic screw-hole models. Conclusion The FNS screw hole demonstrates a relatively lower mechanical risk of femoral head collapse. In contrast, sclerotic screw holes increase this risk, while bone grafting may improve the biomechanical behavior after fixation removal, potentially reducing the likelihood of femoral head collapse.
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Affiliation(s)
- Xishan Li
- Department of Trauma Surgery, Orthopedics and Plastic Surgery, University Medical Center Göttingen, Göttingen, Germany
| | - Xiang Zhou
- Department of Trauma Surgery, Orthopedics and Plastic Surgery, University Medical Center Göttingen, Göttingen, Germany
- Department of Articular and Traumatic Orthopedic Surgery, Fourth People's Hospital of Guiyang, Guiyang, Guizhou, China
| | - Jie Yang
- Department of Trauma Surgery, Orthopedics and Plastic Surgery, University Medical Center Göttingen, Göttingen, Germany
| | - Kai Oliver Böker
- Department of Trauma Surgery, Orthopedics and Plastic Surgery, University Medical Center Göttingen, Göttingen, Germany
| | - Arndt F Schilling
- Department of Trauma Surgery, Orthopedics and Plastic Surgery, University Medical Center Göttingen, Göttingen, Germany
| | - Wolfgang Lehmann
- Department of Trauma Surgery, Orthopedics and Plastic Surgery, University Medical Center Göttingen, Göttingen, Germany
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Wang Q, Sun L, Liu L, Ma T, Li Z, Zhang K, Huang Q. Biomechanical evaluation of the modified proximal femoral nail for the treatment of reverse obliquity intertrochanteric fractures. Sci Rep 2025; 15:3261. [PMID: 39863714 PMCID: PMC11763255 DOI: 10.1038/s41598-025-87951-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2024] [Accepted: 01/23/2025] [Indexed: 01/27/2025] Open
Abstract
The best treatment method for reverse obliquity intertrochanteric fractures (ROIFs) is still under debate. Our team designed the modified proximal femoral nail (MPFN) specially for treating such fractures. The objective of this research was to introduce the MPFN device and compare the biomechanical properties with Proximal Femoral Nail Antirotation (PFNA) and InterTAN nail via finite element modelling. An AO/OTA 31-A3.1 ROIF model was established via Mimics software. Three implants were depicted and assembled on the ROIF models. The axial, bending, and torsion loads were simulated to test stress and displacement of three fixation models. Compared to the PFNA and InterTAN models, the MPFN model had more dispersed stress distribution under axial loads of 2,100 N. The MPFN showed lower von Mises stress on bones compared with that of PFNA and InterTAN in axial loads. In term of maximum displacement, the MPFN had a 12.6% reduction compared to the PFNA model in axial load case. In bending and torsion loads, the MPFN model also demonstrated better biomechanical properties than the PFNA and InterTAN models. The modified proximal femoral nail presented the best biomechanical performance, followed by the InterTAN nail, and the PFNA for fixing reverse obliquity intertrochanteric fractures. The MPFN has the potential to be a promising device for patients with ROIFs.
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Affiliation(s)
- Qian Wang
- Department of Orthopedics, Honghui Hospital, Xi'an Jiaotong University, Xi'an, 710054, Shaanxi, China
| | - Liang Sun
- Department of Orthopedics, Honghui Hospital, Xi'an Jiaotong University, Xi'an, 710054, Shaanxi, China
| | - Lu Liu
- Department of Orthopedics, Honghui Hospital, Xi'an Jiaotong University, Xi'an, 710054, Shaanxi, China
| | - Teng Ma
- Department of Orthopedics, Honghui Hospital, Xi'an Jiaotong University, Xi'an, 710054, Shaanxi, China
| | - Zhong Li
- Department of Orthopedics, Honghui Hospital, Xi'an Jiaotong University, Xi'an, 710054, Shaanxi, China
| | - Kun Zhang
- Department of Orthopedics, Honghui Hospital, Xi'an Jiaotong University, Xi'an, 710054, Shaanxi, China.
| | - Qiang Huang
- Department of Orthopedics, Honghui Hospital, Xi'an Jiaotong University, Xi'an, 710054, Shaanxi, China.
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Vom Scheidt A, Pirrung F, Henyš P, Oppelt B, Leithner A, Hammer N, Bergovec M. Plating after tumor curettage in human femora does not efficiently improve torsional stability ex vivo. J Mech Behav Biomed Mater 2025; 161:106798. [PMID: 39504786 DOI: 10.1016/j.jmbbm.2024.106798] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2023] [Revised: 12/22/2023] [Accepted: 11/02/2024] [Indexed: 11/08/2024]
Abstract
BACKGROUND Surgical treatments of benign primary bone tumors of the femur face the challenge of limiting tissue damage and contamination while providing sufficient stabilization to avoid fracture. While no clear treatment guidelines exist, surgical treatment commonly consists of femoral fenestration and curettage with optional filling and plating of the defect. Mono- or bicortical plating of distal femoral defects aim to reduce fracture risk and have been shown to increase axial stability. However, it remains unclear whether plating increases torsional stability of the affected femur. QUESTIONS/PURPOSES This biomechanical study aimed to determine how much additional stability can be achieved by mono- or bicortical plating of femoral defects after fenestration. The following hypotheses were investigated: 1. Preventive plating of distal femur bone defects enhances torsional stability when compared to femoral fenestration alone. 2. A condition close to the intact (nonpathological) bone can be achieved by bone plating. 3. Defect shape influences torsional stability. PATIENTS AND METHODS Thiel embalmed human femora (n = 24) were left intact or subjected to the following surgical treatments (A) defect creation via fenestration, (B) defect with short monocortical plating, (C) defect with long bicortical plating. All femora were torsion tested in midstance position using pre-cycling and testing until failure. Quantitative computed tomography pre and post testing allowed bone mineral density calculation and crack path analysis. Finite element analysis provided insight into defect shape variations. RESULTS Torsion experiments showed no relevant enhancement of torsional stability due to mono- or bicortical plating. There were no significant differences in maximum torque between unplated and plated femora with defect (defect: 35.38 ± 7.53 Nm, monocortical plating: 37.77 ± 9.82 Nm, bicortical plating: 50.27 ± 9.72 Nm, p > 0.05). Maximum torque for all treatment groups was significantly lower compared to intact femora (155-200 Nm, p < 0.001). Cracks originated predominantly from the proximal posterior corner of the defect and intersected with screw holes in plated femora. The influence of variations of the defect corner shapes had no significant influence on maximum torque and angle. CONCLUSION This biomechanical study shows that mono- or bicortical plating is not an effective preventive treatment against torsional failure of femora with distal defects as the resulting maximum torque was drastically reduced compared to intact femora. Thus, the initial hypotheses have to be rejected. As habitual loading of the femur includes a combination of axial and torsional loading, the observed lack of prevention against torsional failure might help to explain the occurrence of fractures despite plating. Future research towards ameliorating clinical outcome should address the role of defect filling with bone cement or bone grafts regarding the improvement of torsional stability after primary bone tumor treatment in the femur.
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Affiliation(s)
- Annika Vom Scheidt
- Department of Macroscopic and Clinical Anatomy, Gottfried Schatz Research Center, Medical University of Graz, Auenbruggerplatz 25, 8036, Graz, Austria.
| | - Felix Pirrung
- Department of Macroscopic and Clinical Anatomy, Gottfried Schatz Research Center, Medical University of Graz, Auenbruggerplatz 25, 8036, Graz, Austria.
| | - Petr Henyš
- Institute of New Technologies and Applied Informatics, Faculty of Mechatronics, Informatics and Interdisciplinary Studies, Technical University of Liberec, Studentská 1402/2, Liberec, 461 17, Czech Republic.
| | - Birgit Oppelt
- Division for Pediatric Radiology, Department of Radiology, Medical University of Graz, Auenbruggerplatz 34, 8036, Graz, Austria.
| | - Andreas Leithner
- Department of Orthopedics and Trauma, Medical University of Graz, Auenbruggerplatz 5, 8036, Graz, Austria.
| | - Niels Hammer
- Department of Macroscopic and Clinical Anatomy, Gottfried Schatz Research Center, Medical University of Graz, Auenbruggerplatz 25, 8036, Graz, Austria.
| | - Marko Bergovec
- Department of Orthopedics and Trauma, Medical University of Graz, Auenbruggerplatz 5, 8036, Graz, Austria.
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Hollensteiner M, Baumeister D, Mühling M, Greinwald M, Sandriesser S, Hofstätter B, Petersik A, Augat P. Population-specific femur models: A step towards improved osteosynthetic biomechanical testing in orthopaedics. Clin Biomech (Bristol, Avon) 2025; 121:106379. [PMID: 39550926 DOI: 10.1016/j.clinbiomech.2024.106379] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/30/2024] [Revised: 10/29/2024] [Accepted: 11/11/2024] [Indexed: 11/19/2024]
Abstract
BACKGROUND Biomechanical testing using synthetic bone surrogates has become a standard method for evaluating osteosynthesis techniques. However, these surrogates often fail to account for population-specific variations in bone anatomy and mechanical properties, leading to limitations in predicting clinical outcomes. This study addresses this gap by developing and validating a population-specific synthetic femur model for older women of European ethnicity, incorporating variations in geometry and mechanics observed in this demographic. METHODS The femur model was developed using a statistical shaping algorithm and 3D models from women aged 75 to 85 years. Synthetic femora were fabricated using polyurethane, enriched with fillers and additives to mimic osteoporotic bone characteristics. Mechanical testing, including axial compression, four-point bending, and torsion, was performed on synthetic femora and were validated against human osteoporotic femora. FINDINGS The synthetic femora demonstrated comparable mechanical properties to human osteoporotic femora, particularly in flexural and torsional rigidity. Axial stiffness was slightly lower in the synthetic femora but remained within the range of literature values. Statistical analysis revealed significant differences between synthetic and human bones in certain parameters, highlighting the need for population-specific models. INTERPRETATION The developed synthetic femur model offers a promising solution for addressing the limitations of current bone surrogates in biomechanical testing. By incorporating population-specific characteristics these models provide a more accurate representation of human bone, improving the validity of biomechanical evaluations and potentially leading to more equitable treatment outcomes in orthopaedics. Further research is warranted to explore the applicability of these models across different populations and anatomical sites.
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Affiliation(s)
- Marianne Hollensteiner
- Institute for Biomechanics, BG Unfallklinik Murnau, Prof. Küntscher Str. 8, 82418 Murnau, Germany; Institute for Biomechanics, Paracelsus Medical University Salzburg, Strubergasse 21, 5020 Salzburg, Austria.
| | - Dirk Baumeister
- Institute for Biomechanics, BG Unfallklinik Murnau, Prof. Küntscher Str. 8, 82418 Murnau, Germany; Institute for Biomechanics, Paracelsus Medical University Salzburg, Strubergasse 21, 5020 Salzburg, Austria
| | - Mischa Mühling
- Institute for Biomechanics, BG Unfallklinik Murnau, Prof. Küntscher Str. 8, 82418 Murnau, Germany; Institute for Biomechanics, Paracelsus Medical University Salzburg, Strubergasse 21, 5020 Salzburg, Austria
| | - Markus Greinwald
- Institute for Biomechanics, BG Unfallklinik Murnau, Prof. Küntscher Str. 8, 82418 Murnau, Germany; Institute for Biomechanics, Paracelsus Medical University Salzburg, Strubergasse 21, 5020 Salzburg, Austria
| | - Sabrina Sandriesser
- Institute for Biomechanics, BG Unfallklinik Murnau, Prof. Küntscher Str. 8, 82418 Murnau, Germany; Institute for Biomechanics, Paracelsus Medical University Salzburg, Strubergasse 21, 5020 Salzburg, Austria
| | - Bernhard Hofstätter
- T & E Simulation, Stryker Trauma GmbH, Prof. Küntscher Str. 1-5, 24232 Schönkirchen, Germany
| | - Andreas Petersik
- T & E Simulation, Stryker Trauma GmbH, Prof. Küntscher Str. 1-5, 24232 Schönkirchen, Germany
| | - Peter Augat
- Institute for Biomechanics, BG Unfallklinik Murnau, Prof. Küntscher Str. 8, 82418 Murnau, Germany; Institute for Biomechanics, Paracelsus Medical University Salzburg, Strubergasse 21, 5020 Salzburg, Austria
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Zhang X, Zhang Y, Huang S, Qi X, Li W, Lv Y, Zhu Z. Biomechanical effects of FNS on femoral neck fractures based on different reduction quality: finite element analysis. BMC Musculoskelet Disord 2024; 25:914. [PMID: 39548463 PMCID: PMC11566252 DOI: 10.1186/s12891-024-08041-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/08/2024] [Accepted: 11/07/2024] [Indexed: 11/18/2024] Open
Abstract
BACKGROUND AND OBJECTIVE The femoral neck system (FNS) has been extensively studied and applied for the treatment of young patients with femoral neck fractures. The purpose of this study was to explore the biomechanical impact variations in reduction qualities on femoral neck fractures, considering factors such as tip-apex distance, the positioning of the bolt in the cortical corridor of the femoral neck, and bone mineral density. MATERIALS AND METHODS A randomly selected volunteer was recruited, whose clinical data on the femur were collected to establish finite element models for positive reduction, anatomical reduction, and negative reduction respectively. Based on the constructed models, different scenarios were established by varying the tip-apex distance, bone mineral density, and positioning of the bolt in the cortical corridor of the femoral neck. Under a vertical load of 2100 N, the displacement and Von Mises stress (VMS) distribution of each group of models were evaluated through simulation testing. RESULTS Under a load of 2100 N, the maximum VMS values of the femoral neck system and femoral head was recorded during negative reduction, 968.85 MPa and 80.09 MPa respectively. In addition, factors influencing the negative reduction of FNS and the femoral head were identified to be the tip-apex distance > 10 mm, the presence of osteoporosis, and the bolt positioned in the lower-middle to the third part of the cortical corridor of the femoral neck. CONCLUSION The displacement and stress of negative reduction were greater than those of positive reduction and anatomical reduction when the tip-apex distance > 10 mm, and the bolt was situated in the lower-middle to the third part of the cortical corridor of the femoral neck, and in the presence of osteoporosis. This means that we recommend positive repositioning over negative repositioning when anatomical repositioning is not clinically feasible.
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Affiliation(s)
- Xu Zhang
- Department of Orthopaedics, The Second Affiliated Hospital of XuZhou Medical University, No 32 Meijian Road, Xuzhou, Jiangsu, 221000, China.
- Graduate school of Xuzhou Medical University, Xuzhou, Jiangsu, 221000, China.
| | - Yazhong Zhang
- Department of Orthopaedics, The Second Affiliated Hospital of XuZhou Medical University, No 32 Meijian Road, Xuzhou, Jiangsu, 221000, China
| | - Shaolong Huang
- Department of Orthopaedics, The Second Affiliated Hospital of XuZhou Medical University, No 32 Meijian Road, Xuzhou, Jiangsu, 221000, China
- Graduate school of Xuzhou Medical University, Xuzhou, Jiangsu, 221000, China
| | - Xiangyu Qi
- Department of Orthopaedics, The Second Affiliated Hospital of XuZhou Medical University, No 32 Meijian Road, Xuzhou, Jiangsu, 221000, China
- Graduate school of Xuzhou Medical University, Xuzhou, Jiangsu, 221000, China
| | - Wenbo Li
- Department of Orthopaedics, The Second Affiliated Hospital of XuZhou Medical University, No 32 Meijian Road, Xuzhou, Jiangsu, 221000, China
| | - Yongxiang Lv
- Department of Orthopaedics, The Second Affiliated Hospital of XuZhou Medical University, No 32 Meijian Road, Xuzhou, Jiangsu, 221000, China
| | - Ziqiang Zhu
- Department of Orthopaedics, The Second Affiliated Hospital of XuZhou Medical University, No 32 Meijian Road, Xuzhou, Jiangsu, 221000, China.
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Schulz AP, Münch M, Barth T, Kowald B, Frese J, Behrends L, Hartel M. Initial construct stability of long cephalomedullary nails with superior locking for a complex trochanteric fracture model AO31A2.2- a biomechanical study. J Orthop Surg Res 2024; 19:728. [PMID: 39506795 PMCID: PMC11542236 DOI: 10.1186/s13018-024-05079-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/24/2024] [Accepted: 09/13/2024] [Indexed: 11/08/2024] Open
Abstract
BACKGROUND Complex fractures of the trochanteric region, as well as fractures located in the directly subtrochanteric region, are controversially discussed around the world regarding the nail type to be used. A long nail is recommended by manufacturers but requires longer surgical and fluoroscopy times. A possible solution could be a nail with an appropriate length which can be locked in a minimally invasive manner by the main aiming device. We aimed to determine if such a nail model (DCN SL nail, SWEMAC, Linköping, Sweden) offers similar structural stability on biomechanical testing on artificial bone as a standard long nail when used to treat complex trochanteric fractures and compared it to long nails usually used in this setting. METHODS An osteoporotic bone model was chosen. The Swemac Hansson DCN Nail System was used as osteosynthesis material. Two types of nails were chosen: a superior lock nail which can be implanted with a singular targeting device, and a long nail with distal locking using free-hand technique. AO31A2.2 fractures were simulated in a standardised manner. Axial height of the construct, varus collapse, and rotational deformity directly after nail insertion were simulated. A Universal Testing Machine was used. Measurements were made with a stereo-optic tracking system. FINDINGS There was a detectable difference in the axial fracture movement resulting in narrowing of the fracture gap. There was no difference in varus collapse or rotational deformity between the nail variants CONCLUSION: We conclude that there are small differences which are clinically insignificant and that a superior locking nail can safely be used to manage complex trochanteric fractures.
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Affiliation(s)
- Arndt-Peter Schulz
- BG Klinikum Hamburg, Zentrum Klinische Forschung, Bergedorfer Strasse 10, 21033, Hamburg, Germany.
- Sektion Medizin, Universität zu Lübeck, Ratzeburger Allee 160, 23568, Lübeck, Germany.
- Fraunhofer Research Institution for Individualized and Cell-Based Medical Engineering IMTE, Mönkhofer Weg 239 a, 23562, Lübeck, Germany.
| | - Matthias Münch
- BG Klinikum Hamburg, Zentrum Klinische Forschung, Bergedorfer Strasse 10, 21033, Hamburg, Germany
- Fraunhofer Research Institution for Individualized and Cell-Based Medical Engineering IMTE, Mönkhofer Weg 239 a, 23562, Lübeck, Germany
| | - Tobias Barth
- BG Klinikum Hamburg, Zentrum Klinische Forschung, Bergedorfer Strasse 10, 21033, Hamburg, Germany
- Fraunhofer Research Institution for Individualized and Cell-Based Medical Engineering IMTE, Mönkhofer Weg 239 a, 23562, Lübeck, Germany
| | - Birgitt Kowald
- BG Klinikum Hamburg, Zentrum Klinische Forschung, Bergedorfer Strasse 10, 21033, Hamburg, Germany
| | - Jasper Frese
- BG Klinikum Hamburg, Zentrum Klinische Forschung, Bergedorfer Strasse 10, 21033, Hamburg, Germany
| | - Lina Behrends
- Fraunhofer Research Institution for Individualized and Cell-Based Medical Engineering IMTE, Mönkhofer Weg 239 a, 23562, Lübeck, Germany
| | - Maximilian Hartel
- BG Klinikum Hamburg, Zentrum Klinische Forschung, Bergedorfer Strasse 10, 21033, Hamburg, Germany
- Department of Trauma Surgery and Orthopedics, University Medical Center Hamburg-Eppendorf (UKE), Martinistrasse 52, 20246, Hamburg, Germany
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Zhou X, Li X, Böker KO, Schilling AF, Lehmann W. Biomechanical investigation of positive reduction in the femoral neck fracture: a finite element analysis. Front Bioeng Biotechnol 2024; 12:1374299. [PMID: 39444522 PMCID: PMC11496117 DOI: 10.3389/fbioe.2024.1374299] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2024] [Accepted: 09/26/2024] [Indexed: 10/25/2024] Open
Abstract
Background Gotfried positive reduction offers an alternative strategy for femoral neck fracture (FNF) when achieving anatomical reduction is challenging. However, the biomechanical consequences of positive reduction remain unclear. The purpose of this study was to investigate the biomechanical behavior of positive reduction across different Pauwels classification, providing a reference for quantifying positive reduction in clinical practice. Methods Three-dimensional (3D) models of FNF were established and categorized according to the Pauwels classifications (Pauwels I, II, and III), each of them contained seven models with different reduction qualities, including an anatomical reduction model, two negative reduction models, and four positive reduction models, all of which were stabilized with dynamic hip screws (DHS) and cannulated screws (CS). We investigated the maximal von-Mises stress of internal fixation and proximal femoral, femoral fragment displacement, and maximal von-Mises strain at the proximal fragment fracture site when a 2100 N load was applied to the femoral head. Results The maximum von-Mises stress on the internal fixators in each Pauwels group was lowest in the anatomical reduction model. In the Pauwels I group, positive reduction exceeding 3 mm resulted in the maximum von-Mises stress on the internal fixators surpassing that of the negative reduction model. For the Pauwels II group, positive reduction beyond 2 mm led to the maximum von-Mises stress on the internal fixators exceeding that of the negative reduction model. In the Pauwels III group, positive reduction beyond 1 mm caused the maximum von-Mises stress on the internal fixators to be higher than that of the negative reduction model. The maximum von-Mises strain at the fracture site of proximal femur fragment increased with positive reduction. Varus displacement increased in positive reduction models as the Pauwels angle rose, potentially exacerbating rotation deformity in Pauwels III group. Conclusion Excessive positive reduction may increase the risk of FNF failure after internal fixation. From a biomechanical stability perspective, positive reduction should be limited to 3 mm or below in the Pauwels I group, restricted to not exceed 2 mm in the Pauwels II group, and should not exceed 1 mm in the Pauwels III group. Negative reduction should be avoided in all Pauwels groups.
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Affiliation(s)
- Xiang Zhou
- Department of Trauma Surgery, Orthopedics and Plastic Surgery, University Medical Center Göttingen, Göttingen, Germany
- Department of Articular and Traumatic Orthopedic Surgery, Fourth People’s Hospital of Guiyang, Guiyang, Guizhou, China
| | - Xishan Li
- Department of Trauma Surgery, Orthopedics and Plastic Surgery, University Medical Center Göttingen, Göttingen, Germany
| | - Kai Oliver Böker
- Department of Trauma Surgery, Orthopedics and Plastic Surgery, University Medical Center Göttingen, Göttingen, Germany
| | - Arndt F. Schilling
- Department of Trauma Surgery, Orthopedics and Plastic Surgery, University Medical Center Göttingen, Göttingen, Germany
| | - Wolfgang Lehmann
- Department of Trauma Surgery, Orthopedics and Plastic Surgery, University Medical Center Göttingen, Göttingen, Germany
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Olivares-Hernandez AE, Olivares-Robles MA, Méndez-Méndez JV, Gutiérrez-Camacho C. Microfilm Coatings: A Biomaterial-Based Strategy for Modulating Femoral Deflection. J Funct Biomater 2024; 15:283. [PMID: 39452582 PMCID: PMC11508653 DOI: 10.3390/jfb15100283] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2024] [Revised: 09/16/2024] [Accepted: 09/23/2024] [Indexed: 10/26/2024] Open
Abstract
Wear on the surface of the femoral head increases the risk of hip and femur fractures. Biomechanical experiments conducted on the femur are based on its bending and torsional rigidities. Studies regarding the deflection of the femur bone when the femoral head is coated with microfilms composed of durable and compatible biomaterials are poor. This study aimed to investigate the effects of different biomaterial microfilm coatings over the femoral head on the deflection of the human femur. We utilized 2023 R1 finite element analysis (FEA) software to model the directional deformation on the femoral head and examine the femur's deflection with varying microfilm thicknesses. The deflection of the femur bone was reported when the femoral head was uncoated and coated with titanium, stainless steel, and pure gold microfilms of different thicknesses (namely, 50, 75, and 100 μm). Our results show that the femur's minimum and maximum deflection occurred for stainless steel and gold, respectively. The deformation of the femur was lower when the femoral head was coated with a 50-micrometer microfilm of stainless steel, compared to the deformation obtained with gold and titanium. When the thickness of the microfilm for each of the materials was increased, the deformation continued to decrease. The minimum deformation of the femur occurred for a thickness of 100 μm with stainless steel, followed by titanium and gold. The difference in the directional deformation of the femur between the materials was more significant when the coating was 100 μm, compared to the thicknesses of 50 and 75 μm. The findings of this study are expected to significantly contribute to the development of advanced medical techniques to enhance the quality of life for patients with femur bone-related issues. This information can be used to develop more resilient coatings that can withstand wear and tear.
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Affiliation(s)
- Ana Elisabeth Olivares-Hernandez
- Instituto Politecnico Nacional, Seccion de Estudios de Posgrado e Investigacion, Escuela Nacional de Ciencias Biologicas, Ciudad de Mexico 11340, Mexico
| | - Miguel Angel Olivares-Robles
- Instituto Politecnico Nacional, Seccion de Estudios de Posgrado e Investigacion, Escuela Superior de Ingenieria Mecanica y Electrica Unidad Culhuacan, Coyoacan, Ciudad de Mexico 04430, Mexico
| | - Juan Vicente Méndez-Méndez
- Instituto Politecnico Nacional, Centro de Nanociencias y Micro y Nanotecnologías, “Unidad Profesional Adolfo Lopez Mateos”, Luis Enrico Erro s/n, Ciudad de Mexico 07738, Mexico;
| | - Claudia Gutiérrez-Camacho
- Hospital Infantil de Mexico Federico Gomez, Direccion de Enseñanza y Desarrollo Académico, Ciudad de Mexico 06720, Mexico;
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Tang Z, Lv Y, Zhu Z, Lu Y, Zhou H, Zhang Y, Liao Y, Wang B. Biomechanical characteristic differences of two new types of intramedullary nail devices in the treatment of comminuted intertrochanteric fractures of femur: a comparative study based on finite element analysis. J Orthop Surg Res 2024; 19:583. [PMID: 39304891 DOI: 10.1186/s13018-024-05073-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/29/2024] [Accepted: 09/11/2024] [Indexed: 09/22/2024] Open
Abstract
OBJECTIVE Given the recent application of two new types of intramedullary nail devices in the treatment of comminuted femoral intertrochanteric fractures (CFIFs), there is still a lack of deep understanding and comparative evaluation of their biomechanical properties. Therefore, this study aims to systematically compare the advantages and disadvantages of these two new devices with traditional proximal femoral nail antirotation (PFNA) and InterTan nails in the fixation of CFIFs through finite element analysis. METHODS Based on the validated finite element model, this study constructed an accurate CFIFs model. In this model, PFNA, InterTan nails, proximal femoral bionic nails (PFBN), and new intramedullary systems (NIS) were implanted, totaling four groups of finite element models. Each group of models was subjected to simulation tests under a vertical load of 2100 N to evaluate the displacement and Von Mises stress (VMS) distribution of the femur and intramedullary nail devices. RESULTS Under a vertical load of 2100 N, a comparative analysis of the four finite element models showed that the NIS device exhibited the most superior performance in terms of peak displacement, while the PFNA device performed relatively poorly. Although the NIS device had the highest peak stress in the femur, it had the smallest peak displacement of both the femur and intramedullary nail devices, and the peak stress was mainly concentrated on the lateral side of the femur, with significantly lower stress in the proximal femur compared to the other three intramedullary nail devices. In contrast, the PFBN device had the lowest peak stress in the femur, and its peak displacement of both the femur and intramedullary nail devices was also less than that of PFNA and InterTan nails. CONCLUSION This study demonstrates that in the treatment of CFIFs, PFBN and NIS devices exhibit superior biomechanical performance compared to traditional PFNA and InterTan nail devices. Especially the NIS device, which can achieve good biomechanical results when fixing femoral intertrochanteric fractures with missing medial wall. Therefore, both PFBN and NIS devices can be considered reliable closed reduction and internal fixation techniques for the treatment of CFIFs, with potential clinical application value.
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Affiliation(s)
- Zhongjian Tang
- Department of Orthopaedics, The Second Affiliated Hospital of XuZhou Medical University, Xuzhou, 221000, China
- Graduate School of Xuzhou Medical University, Xuzhou, China
| | - Yongxiang Lv
- Department of Orthopaedics, The Second Affiliated Hospital of XuZhou Medical University, Xuzhou, 221000, China
| | - Zhexi Zhu
- Department of Orthopaedics, The Second Affiliated Hospital of XuZhou Medical University, Xuzhou, 221000, China
- Graduate School of Xuzhou Medical University, Xuzhou, China
| | - Yafei Lu
- Department of Orthopaedics, The Second Affiliated Hospital of XuZhou Medical University, Xuzhou, 221000, China
- Graduate School of Xuzhou Medical University, Xuzhou, China
| | - Haibin Zhou
- Department of Orthopaedics, The Second Affiliated Hospital of XuZhou Medical University, Xuzhou, 221000, China
- Graduate School of Xuzhou Medical University, Xuzhou, China
| | - Yazhong Zhang
- Department of Orthopaedics, The Second Affiliated Hospital of XuZhou Medical University, Xuzhou, 221000, China
| | - Yifeng Liao
- Department of Orthopaedics, The Second Affiliated Hospital of XuZhou Medical University, Xuzhou, 221000, China
| | - Bin Wang
- Department of Orthopaedics, The Second Affiliated Hospital of XuZhou Medical University, Xuzhou, 221000, China.
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Hollensteiner M, Sandriesser S, Libert J, Spitzer-Vanech L, Baumeister D, Greinwald M, Mühling M, Augat P. Biomechanical validation of novel polyurethane-resin synthetic osteoporotic femoral bones in axial compression, four-point bending and torsion. Med Eng Phys 2024; 130:104210. [PMID: 39160032 DOI: 10.1016/j.medengphy.2024.104210] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2023] [Revised: 06/08/2024] [Accepted: 07/16/2024] [Indexed: 08/21/2024]
Abstract
In addition to human donor bones, bone models made of synthetic materials are the gold standard substitutes for biomechanical testing of osteosyntheses. However, commercially available artificial bone models are not able to adequately reproduce the mechanical properties of human bone, especially not human osteoporotic bone. To overcome this issue, new types of polyurethane-based synthetic osteoporotic bone models have been developed. Its base materials for the cancellous bone portion and for the cortical portion have already been morphologically and mechanically validated against human bone. Thus, the aim of this study was to combine the two validated base materials for the two bone components to produce femur models with real human geometry, one with a hollow intramedullary canal and one with an intramedullary canal filled with synthetic cancellous bone, and mechanically validate them in comparison to fresh frozen human bone. These custom-made synthetic bone models were fabricated from a computer-tomography data set in a 2-step casting process to achieve not only the real geometry but also realistic cortical thicknesses of the femur. The synthetic bones were tested for axial compression, four-point bending in two planes, and torsion and validated against human osteoporotic bone. The results showed that the mechanical properties of the polyurethane-based synthetic bone models with hollow intramedullary canals are in the range of those of the human osteoporotic femur. Both, the femur models with the hollow and spongy-bone-filled intramedullary canal, showed no substantial differences in bending stiffness and axial compression stiffness compared to human osteoporotic bone. Torsional stiffnesses were slightly higher but within the range of human osteoporotic femurs. Concluding, this study shows that the innovative polyurethane-based femur models are comparable to human bones in terms of bending, axial compression, and torsional stiffness.
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Affiliation(s)
- Marianne Hollensteiner
- Institute for Biomechanics, BG Unfallklinik Murnau, Prof. Küntscher Str. 8, 82418 Murnau, Germany; Institute for Biomechanics, Paracelsus Medical University Salzburg, Strubergasse 21, 5020 Salzburg, Austria.
| | - Sabrina Sandriesser
- Institute for Biomechanics, BG Unfallklinik Murnau, Prof. Küntscher Str. 8, 82418 Murnau, Germany; Institute for Biomechanics, Paracelsus Medical University Salzburg, Strubergasse 21, 5020 Salzburg, Austria
| | - Jessica Libert
- Institute for Biomechanics, BG Unfallklinik Murnau, Prof. Küntscher Str. 8, 82418 Murnau, Germany; Faculty of Mechanical and Process Engineering, Offenburg University of Applied Sciences, Badstraße 24, 77652 Offenburg, Germany
| | - Lily Spitzer-Vanech
- Institute for Biomechanics, BG Unfallklinik Murnau, Prof. Küntscher Str. 8, 82418 Murnau, Germany; Northeastern University, Bioengineering Department, 805 Columbus Avenue, Boston, MA 02120, USA
| | - Dirk Baumeister
- Institute for Biomechanics, BG Unfallklinik Murnau, Prof. Küntscher Str. 8, 82418 Murnau, Germany; Institute for Biomechanics, Paracelsus Medical University Salzburg, Strubergasse 21, 5020 Salzburg, Austria
| | - Markus Greinwald
- Institute for Biomechanics, BG Unfallklinik Murnau, Prof. Küntscher Str. 8, 82418 Murnau, Germany; Institute for Biomechanics, Paracelsus Medical University Salzburg, Strubergasse 21, 5020 Salzburg, Austria
| | - Mischa Mühling
- Institute for Biomechanics, BG Unfallklinik Murnau, Prof. Küntscher Str. 8, 82418 Murnau, Germany; Institute for Biomechanics, Paracelsus Medical University Salzburg, Strubergasse 21, 5020 Salzburg, Austria
| | - Peter Augat
- Institute for Biomechanics, BG Unfallklinik Murnau, Prof. Küntscher Str. 8, 82418 Murnau, Germany; Institute for Biomechanics, Paracelsus Medical University Salzburg, Strubergasse 21, 5020 Salzburg, Austria
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Zhang X, Zhang Y, Qi X, Huang S, Lv Y, Li W, Li C, Zhu Z. Risk of internal fixation treatment in intertrochanteric fracture based on different lateral femoral wall thickness: finite element analysis. BMC Musculoskelet Disord 2024; 25:462. [PMID: 38872122 PMCID: PMC11170903 DOI: 10.1186/s12891-024-07582-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/28/2024] [Accepted: 06/10/2024] [Indexed: 06/15/2024] Open
Abstract
OBJECTIVE The thickness of the lateral femoral wall, which is an important indicator for evaluating the stability and integrity of intertrochanteric fractures, has been widely studied in recent years. However, as a typical representative of internal fixation treatment, there are few reports on the biomechanical comparison between PFNA and DHS + CS. This study focused primarily on the biomechanical effects of different lateral femoral wall thicknesses on two types of internal fixation through finite element analysis. METHODS We randomly recruited a healthy adult and collected his femoral CT data to establish a model of femoral intertrochanteric fracture with different lateral femoral wall thicknesses. Following PFNA and DHS + CS fixation, femoral models were simulated, and variations in stress and displacement of the internal fixation and femoral head were recorded under the same physiological load. RESULTS First, finite element mechanical analysis revealed that the stress and displacement of the internal fixation and femoral head were lower in the femoral model after PFNA fixation than in the DHS + CS model. Second, as the outer wall thickness decreased, the stress and deformation endured by both types of internal fixation gradually increased. CONCLUSIONS Finite element analysis determined that PFNA exhibits significantly better biomechanical stability than DHS + CS when subjected to varying lateral femoral wall thicknesses. Moreover, lateral femoral wall thickness substantially affects the stability of the two internal fixation biomechanical environments. When the thickness of the lateral femoral wall is too small, we do not recommend using extramedullary fixation because there is a significant risk of internal fixation fracture.
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Affiliation(s)
- Xu Zhang
- Department of Orthopaedics, The Second Affiliated Hospital of XuZhou Medical University, Xuzhou, 221000, China
- Graduate School of Xuzhou Medical University, Xuzhou, Jiangsu, 221000, China
| | - Yazhong Zhang
- Department of Orthopaedics, The Second Affiliated Hospital of XuZhou Medical University, Xuzhou, 221000, China
| | - Xiangyu Qi
- Department of Orthopaedics, The Second Affiliated Hospital of XuZhou Medical University, Xuzhou, 221000, China
- Graduate School of Xuzhou Medical University, Xuzhou, Jiangsu, 221000, China
| | - Shaolong Huang
- Department of Orthopaedics, The Second Affiliated Hospital of XuZhou Medical University, Xuzhou, 221000, China
- Graduate School of Xuzhou Medical University, Xuzhou, Jiangsu, 221000, China
| | - Yongxiang Lv
- Department of Orthopaedics, The Second Affiliated Hospital of XuZhou Medical University, Xuzhou, 221000, China
| | - Wenbo Li
- Department of Orthopaedics, The Second Affiliated Hospital of XuZhou Medical University, Xuzhou, 221000, China
| | - Chao Li
- Department of Orthopaedics, The Second Affiliated Hospital of XuZhou Medical University, Xuzhou, 221000, China
| | - Ziqiang Zhu
- Department of Orthopaedics, The Second Affiliated Hospital of XuZhou Medical University, Xuzhou, 221000, China.
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Yoon YC, Kim JW, Kim TK, Oh CW, Park KH, Lee JH. Comparative biomechanical analysis of reconstruction and cephalomedullary nails in the treatment of osteoporotic subtrochanteric fractures. Injury 2024; 55:111512. [PMID: 38537396 DOI: 10.1016/j.injury.2024.111512] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/21/2024] [Revised: 03/05/2024] [Accepted: 03/18/2024] [Indexed: 05/24/2024]
Abstract
INTRODUCTION This study aimed to compare the biomechanical properties of two types of intramedullary nails - reconstruction nails (RCN) and cephalomedullary nails (CMN) - each with different proximal fixations, in a model of an osteoporotic subtrochanteric femoral fracture. This study focused on assessing stiffness and load to failure of RCN and CMN nails to provide insight into their clinical applications in osteoporotic fracture treatments. MATERIALS AND METHODS Ten synthetic osteoporotic femoral models were used to generate a comminuted subtrochanteric fracture model. Five femurs were fixed using an RCN, and the remaining five were fixed using a CMN. The constructs were subjected to axial compression to measure their structural stiffness, load to failure, and failure modes. RESULTS The CMN group demonstrated a slightly higher load to failure (mean, 2250 N) than the RCN group (mean, 2100 N), which was statistically significant (p = 0.008). However, the stiffness in both groups was statistically similar (RCN, 250 N/mm; CMN, 255 N/mm; p = 0.69). Both groups showed a load to failure exceeding 1500 N, a typically exerted load on the femoral head by a 75 kg individual. The failure patterns differed, with CMN failures starting at the nail insertion area and RCN failures starting at the reconstruction screw area. CONCLUSION The RCN offers stiffness comparable to that of the CMN; although its load to failure is slightly lower than that of the CMN, it still exceeds the physiological tolerance limit. These findings suggest that the RCN is a viable alternative for treating osteoporotic subtrochanteric fractures.
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Affiliation(s)
- Yong-Cheol Yoon
- Orthopedic Trauma Division, Trauma Center, College of Medicine, Gachon University, Incheon, Republic of Korea
| | - Joon-Woo Kim
- Department of Orthopedic Surgery, School of Medicine, Kyungpook National University, Kyungpook National University Hospital, Daegu, Republic of Korea
| | - Tae-Kong Kim
- Department of Orthopedic Surgery, School of Medicine, Kyungpook National University, Kyungpook National University Hospital, Daegu, Republic of Korea
| | - Chang-Wug Oh
- Department of Orthopedic Surgery, School of Medicine, Kyungpook National University, Kyungpook National University Hospital, Daegu, Republic of Korea; Joint Institute for Regenerative Medicine, Kyungpook National University, Bio-Medical Research Institute, Kyungpook National University Hospital, Daegu, Republic of Korea.
| | - Kyeong-Hyeon Park
- Department of Orthopedic Surgery, Severance Children's Hospital, Yonsei University College of Medicine, Seoul, Republic of Korea
| | - Jin-Han Lee
- Department of Orthopedic Surgery, School of Medicine, Kyungpook National University, Kyungpook National University Hospital, Daegu, Republic of Korea
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Li SJ, Huang HJ, Li CT, Hu GJ, Yu F, Liu YB. Mechanical effect of changed femoral neck ante-version angles on the stability of an intertrochanteric fracture fixed with PFNA: A finite element analysis. Heliyon 2024; 10:e31480. [PMID: 38813167 PMCID: PMC11133928 DOI: 10.1016/j.heliyon.2024.e31480] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2023] [Revised: 05/16/2024] [Accepted: 05/16/2024] [Indexed: 05/31/2024] Open
Abstract
Objective Change of femoral neck ante-version angle postoperatively due to inadequate reduction could result in unsatisfying treatment outcome of intertrochanteric fracture. However, the influence of increased or decreased femoral neck ante-version on the biomechanical stability of the bone-implant complex has rarely been studied. Methods A finite element model of a complete normal human femur with normal femoral neck ante-version as 13° was established accurately by scanning a 64 year old female femur. The models of 31-A1.1 intertrochanteric fractures with different femoral neck ante-version angles of 3°, 5.5°, 8°, 10.5°, 13°, 15.5°, 18°, 20.5°, 23° were created. They were assembled with a proximal femoral nail anti-rotation (PFNA) device. The biomechanical differences with varying femoral neck ante-version angles were compared using finite element analysis method. Results As the femoral neck ante-version angle gradually increased from 13° to 23°with a gradient of 2.5°, the peak von Mises stress was gradually increased from 137.82 MPa to 276.02 MPa. Similarly, the peak von Mises stress was gradually increased from 137.82 MPa to 360.12 MPa with the femoral neck ante-version angle decreased from 13° to 3°. When decreased ante-version angle of 7.5° and increased ante-version angle of 10° will exceed the yield strength of femoral (240.32 MPa), the risk of femoral fracture will increase significantly. The maximum displacement of the femur was significantly reduced for increased ante-version models than for decreased ante-version models, whether the changes of ante-version angles were 2.5°, 5°, 7.5° or 10°. The maximum stress of PFNA was found in the intersection of main nail and helical blade, and became greater gradually as the ante-version angle increased or decreased with a gradient of 2.5°. The maximum stress of PFNA was presented in the model 5.5° with the maximum stress of 724.42 MPa (near to the yield strength of titanium alloy of 700-1000 MPa), producing the breakage risk of PFNA. The maximum displacement of the PFNA was significantly reduced for increased ante-version models than for decreased ante-version models, whether the changes of ante-version angles were 2.5°, 5°, 7.5° or 10°. Conclusion Based on the results of present study, it was demonstrated that the anatomical reduction of femoral neck ante-version was vital to secure the optimal stability. Abnormal femoral ante-version could increase the potential risk of failure for intertrochanteric fracture after PFNA. The stability of increased femoral ante-version (less than 10°) was superior to the stability of decreased ante-version (less than 5°) for the cases of difficulty to acquire anatomical reduction. The clinical implication of the finding was that increased femoral neck ante-version had an advantage of mechanical stability towards the decreased femoral neck ante-version for the cases of comminuted intertrochanteric fracture and failure of anatomical reduction.
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Affiliation(s)
- Song-Jian Li
- Orthopedics Center, Department of Orthopedics and Traumatology, Zhujiang Hospital, Southern Medical University, China
| | - Hua-Jian Huang
- Orthopedics Center, Department of Orthopedics and Traumatology, Zhujiang Hospital, Southern Medical University, China
| | - Chen-Tian Li
- Orthopedics Center, Department of Orthopedics and Traumatology, Zhujiang Hospital, Southern Medical University, China
| | - Guo-Ju Hu
- Orthopedics Center, Department of Orthopedics and Traumatology, Zhujiang Hospital, Southern Medical University, China
| | - Fei Yu
- College of Management, Guangdong Polytechnic Normal University, China
| | - Yu-Bin Liu
- Orthopedics Center, Department of Orthopedics and Traumatology, Zhujiang Hospital, Southern Medical University, China
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Tang Z, Zhang Y, Huang S, Zhu Z, Zhou C, Zhu Z, Wang Y, Wang B. Biomechanical study of a biplanar double support screw (BDSF) technique based on Pauwels angle in femoral neck fractures: finite element analysis. Front Bioeng Biotechnol 2024; 12:1358181. [PMID: 38812913 PMCID: PMC11133638 DOI: 10.3389/fbioe.2024.1358181] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2023] [Accepted: 04/19/2024] [Indexed: 05/31/2024] Open
Abstract
Objective The objective of the present study is to conduct a comparative analysis of the biomechanical advantages and disadvantages associated with a biplanar double support screw (BDSF) internal fixation device. Methods Two distinct femoral neck fracture models, one with a 30° angle and the other with a 70° angle, were created using a verified and effective finite element model. Accordingly, a total of eight groups of finite element models were utilized, each implanted with different configurations of fixation devices, including distal screw 150° BDSF, distal screw 165° BDSF, 3 CLS arranged in an inverted triangle configuration, and 4 CLS arranged in a "α" configuration. Subsequently, the displacement and distribution of Von Mises stress (VMS) in the femur and internal fixation device were assessed in each fracture group under an axial load of 2100 N. Results At Pauwels 30° Angle, the femur with a 150°-BDSF orientation exhibited a maximum displacement of 3.17 mm, while the femur with a 165°-BDSF orientation displayed a maximum displacement of 3.13 mm. When compared with the femoral neck fracture model characterized by a Pauwels Angle of 70°, the shear force observed in the 70° model was significantly higher than that in the 30° model. Conversely, the stability of the 30° model was significantly superior to that of the 70° model. Furthermore, in the 70° model, the BDSF group exhibited a maximum femur displacement that was lower than both the 3CCS (3.46 mm) and 4CCS (3.43 mm) thresholds. Conclusion The biomechanical properties of the BDSF internal fixation device are superior to the other two hollow screw internal fixation devices. Correspondingly, superior biomechanical outcomes can be achieved through the implementation of distal screw insertion at an angle of 165°. Thus, the BDSF internal fixation technique can be considered as a viable closed reduction internal fixation technique for managing femoral neck fractures at varying Pauwels angles.
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Affiliation(s)
- Zhongjian Tang
- Department of Orthopaedics, The Second Affiliated Hospital of XuZhou Medical University, Xuzhou, China
- Graduate School of Xuzhou Medical University, Xuzhou, China
| | - Yazhong Zhang
- Department of Orthopaedics, The Second Affiliated Hospital of XuZhou Medical University, Xuzhou, China
| | - Shaolong Huang
- Department of Orthopaedics, The Second Affiliated Hospital of XuZhou Medical University, Xuzhou, China
- Graduate School of Xuzhou Medical University, Xuzhou, China
| | - Zhexi Zhu
- Department of Orthopaedics, The Second Affiliated Hospital of XuZhou Medical University, Xuzhou, China
- Graduate School of Xuzhou Medical University, Xuzhou, China
| | - Chengqiang Zhou
- Department of Orthopaedics, The Second Affiliated Hospital of XuZhou Medical University, Xuzhou, China
- Graduate School of Xuzhou Medical University, Xuzhou, China
| | - Ziqiang Zhu
- Department of Orthopaedics, The Second Affiliated Hospital of XuZhou Medical University, Xuzhou, China
| | - Yunqing Wang
- Department of Orthopaedics, The Second Affiliated Hospital of XuZhou Medical University, Xuzhou, China
| | - Bin Wang
- Department of Orthopaedics, The Second Affiliated Hospital of XuZhou Medical University, Xuzhou, China
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Nan C, Liu Y, Zhang D, Qin Y, Yu H, Ma Z. Biomechanical changes in the proximal femur before and after removal of femoral neck system. J Orthop Surg Res 2024; 19:290. [PMID: 38735949 PMCID: PMC11089723 DOI: 10.1186/s13018-024-04769-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/03/2024] [Accepted: 05/01/2024] [Indexed: 05/14/2024] Open
Abstract
BACKGROUND As an innovative internal fixation system, FNS (femoral neck system) is increasingly being utilized by surgeons for the treatment of femoral neck fractures. At present, there have been numerous finite element analysis experiments studying the immediate stability of FNS and CSS in treating femoral neck fractures. However, there is scarce mechanical analysis available regarding the effects post internal fixation removal. This study aimed to investigate the alterations in mechanical parameters of the proximal femur before and after the removal of FNS (femoral neck system), and to assess potential distinctions in indicators following the extraction of CSS (Cannulated Screws). METHODS A proximal femur model was reconstructed using finite element numerical techniques. The models for CSS and FNS were formulated utilizing characteristics and parametric definitions. The internal fixation was combined with a normal proximal femur model to simulate the healing state after fracture surgery. Within the framework of static analysis, consistent stress burdens were applied across the entirety of the models. The total deformation and equivalent stress of the proximal femur were recorded before and after the removal of internal fixation. RESULTS Under the standing condition, the total deformation of the model before and after removing CSS was 0.99 mm and 1.10 mm, respectively, indicating an increase of 12%. The total deformation of the model before and after removing FNS was 0.65 mm and 0.76 mm, respectively, indicating an increase of 17%. The equivalent stress for CSS and FNS were 55.21 MPa and 250.67 MPa, respectively. The average equivalent stress on the cross-section of the femoral neck before and after removal of CSS was 7.76 MPa and 6.11 MPa, respectively. The average equivalent stress on the cross-section of the femoral neck before and after removal of FNS was 9.89 MPa and 8.79 MPa, respectively. CONCLUSIONS The retention of internal fixation may contribute to improved stability of the proximal femur. However, there still existed risks of stress concentration in internal fixation and stress shielding in the proximal femur. Compared to CSS, the removal of FNS results in larger bone tunnels and insufficient model stability. Further clinical interventions are recommended to address this issue.
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Affiliation(s)
- Chong Nan
- Department of Orthopedic, Baoding No. 1 Central Hospital, Baoding, Hebei Province, 071000, China
| | - Yuxiu Liu
- Department of Orthopedic, Baoding No. 1 Central Hospital, Baoding, Hebei Province, 071000, China
| | - Di Zhang
- Department of Spinal Surgery, The Third Hospital of Hebei Medical University, Shijiazhuang, Hebei Province, 050000, China
| | - Yazhuo Qin
- Department of Orthopedic, Baoding No. 1 Central Hospital, Baoding, Hebei Province, 071000, China
| | - Hetong Yu
- Department of Orthopedic, Baoding No. 1 Central Hospital, Baoding, Hebei Province, 071000, China
| | - Zhanbei Ma
- Department of Orthopedic, Baoding No. 1 Central Hospital, Baoding, Hebei Province, 071000, China.
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Shahzad F, Christ AB, Kim L, Levy AS, Teven CM, Fabbri N, Nelson JA, Healey JH. Tandem Reconstruction of the Femoral Diaphysis Using an Intercalary Prosthesis and a Fibular Free Flap. J Bone Joint Surg Am 2024; 106:425-434. [PMID: 38127807 PMCID: PMC10932824 DOI: 10.2106/jbjs.23.00211] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/23/2023]
Abstract
BACKGROUND Femoral diaphyseal reconstructions with metal prostheses have mediocre results because of high mechanical forces that result in eventual implant failure. Biological alternatives require prolonged restrictions on weight-bearing and have high rates of infection, nonunion, and fracture. A novel method of utilizing a vascularized fibula in combination with an intercalary prosthesis was developed to complement the immediate stability of the prosthesis with the long-term biological fixation of a vascularized fibular graft. METHODS A prospectively maintained database was retrospectively reviewed to identify patients who underwent reconstruction of an oncological intercalary femoral defect using an intercalary prosthesis and an inline fibular free flap (FFF). They were compared with patients who underwent femoral reconstruction using an intercalary allograft and an FFF. RESULTS Femoral reconstruction with an intercalary metal prosthesis and an FFF was performed in 8 patients, and reconstruction with an allograft and an FFF was performed in 16 patients. The mean follow-up was 5.3 years and 8.5 years, respectively (p = 0.02). In the bioprosthetic group, radiographic union of the fibula occurred in 7 (88%) of 8 patients, whereas in the allograft group, 13 (81%) of 16 patients had allograft union (p = 1.00) and all 16 patients had fibular union (p = 0.33). The mean time to fibular union in the bioprosthetic group was 9.0 months, whereas in the allograft group, the mean time to allograft union was 15.3 months (p = 0.03) and the mean time to fibular union was 12.5 months (p = 0.42). Unrestricted weight-bearing occurred at a mean of 3.7 months in the prosthesis group and 16.5 months in the allograft group (p < 0.01). Complications were observed in 2 (25%) of 8 patients in the prosthesis group and in 13 (81%) of 16 patients in the allograft group (p = 0.02). Neither chemotherapy nor radiation affected fibular or allograft union rates. Musculoskeletal Tumor Society scores did not differ significantly between the groups (mean, 26 versus 28; p = 0.10). CONCLUSIONS Bioprosthetic intercalary femoral reconstruction with a metal prosthesis and an FFF resulted in earlier weight-bearing, a shorter time to union, fewer operations needed for union, and lower complication rates than reconstruction with an allograft and an FFF. LEVEL OF EVIDENCE Therapeutic Level III . See Instructions for Authors for a complete description of levels of evidence.
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Affiliation(s)
- Farooq Shahzad
- Plastic and Reconstructive Surgery Service, Memorial Sloan-Kettering Cancer Center, New York, NY
| | - Alexander B Christ
- Orthopaedic Surgery Service, Memorial Sloan-Kettering Cancer Center, New York, NY
| | - Leslie Kim
- Plastic and Reconstructive Surgery Service, Memorial Sloan-Kettering Cancer Center, New York, NY
| | - Adam S Levy
- Plastic and Reconstructive Surgery Service, Memorial Sloan-Kettering Cancer Center, New York, NY
| | - Chad M Teven
- Plastic and Reconstructive Surgery Service, Memorial Sloan-Kettering Cancer Center, New York, NY
| | - Nicola Fabbri
- Orthopaedic Surgery Service, Memorial Sloan-Kettering Cancer Center, New York, NY
| | - Jonas A Nelson
- Plastic and Reconstructive Surgery Service, Memorial Sloan-Kettering Cancer Center, New York, NY
| | - John H Healey
- Orthopaedic Surgery Service, Memorial Sloan-Kettering Cancer Center, New York, NY
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Erbulut DU, Green N, Grant C, Tetsworth K. Plate fixation optimization for distal femoral fractures with segmental bone loss: Defining the preferred screw distribution using finite element analysis. Injury 2024; 55:111079. [PMID: 37863754 DOI: 10.1016/j.injury.2023.111079] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/17/2023] [Revised: 08/26/2023] [Accepted: 09/26/2023] [Indexed: 10/22/2023]
Abstract
OBJECTIVES Distal femur fractures can exhibit extensive comminution, and open fractures may result in bone loss. These injuries are under high mechanical demands when stabilized with a lateral locked plate (LLP), and are at risk of non-union or implant failure. This study investigates the optimal LLP screw configuration for distal femur fractures with a large metadiaphyseal gap of 5 cm. METHODS A finite element (FE) model, validated against experimentally measured strains and displacement, evaluated pull-out forces and stress concentration on typical implants under clinical conditions corresponding with the 10 % point during the stance phase of the gait cycle. RESULTS Maximum stress was up to 83 % less when the ratio (Cp) between the proximal screw-distribution-length and the distance of the first screw to the fracture was less than 0.2; maximum pull-out force was 99 % less when this ratio was higher than 0.4. CONCLUSIONS Screw configuration based on either normal or osteopenic bone quality plays an important role in determining the risk of construct failure for a major (50 mm) distal femoral metadiaphyseal segmental defect. This study provides valuable information when planning definitive fixation for distal femur fractures with extensive comminution or segmental bone defects, to mitigate the risk of implant failure and subsequent nonunion.
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Affiliation(s)
- Deniz U Erbulut
- Herston Biofabrication Institute, Metro North Hospital and Health Service, Brisbane, QLD, 4029, Australia; Department of Orthopaedic Surgery, The Royal Brisbane and Women's Hospital, Brisbane, QLD, Australia; School of Mechanical and Mining engineering, University of Queensland, Saint Lucia, QLD, Australia.
| | - Nicholas Green
- Herston Biofabrication Institute, Metro North Hospital and Health Service, Brisbane, QLD, 4029, Australia; Department of Orthopaedic Surgery, The Royal Brisbane and Women's Hospital, Brisbane, QLD, Australia
| | - Caroline Grant
- Faculty of Engineering, Queensland University of Technology, Brisbane, QLD, Australia
| | - Kevin Tetsworth
- Herston Biofabrication Institute, Metro North Hospital and Health Service, Brisbane, QLD, 4029, Australia; Department of Orthopaedic Surgery, The Royal Brisbane and Women's Hospital, Brisbane, QLD, Australia; Orthopaedic Research Centre of Australia, Brisbane, QLD, Australia; Limb Reconstruction Unit, Macquarie University Hospital, Sydney, NSW, Australia
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18
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Ding K, Zhu Y, Zhang Y, Li Y, Wang H, Li J, Chen W, Zhang Q, Zhang Y. Proximal femoral bionic nail-a novel internal fixation system for the treatment of femoral neck fractures: a finite element analysis. Front Bioeng Biotechnol 2023; 11:1297507. [PMID: 38116197 PMCID: PMC10728673 DOI: 10.3389/fbioe.2023.1297507] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2023] [Accepted: 11/20/2023] [Indexed: 12/21/2023] Open
Abstract
Introduction: Currently, cannulated screws (CSs) and dynamic hip screws (DHSs) are widely used for the treatment of femoral neck fractures, but the postoperative complications associated with these internal fixations remain high. In response to this challenge, our team proposes a new approach involving triangular-supported fixation and the development of the proximal femoral bionic nail (PFBN). The primary objective of this study is to investigate the biomechanical differences among CSs, DHSs, and the PFBN in their capacity to stabilize femoral neck fractures. Methods: A normal proximal femur model was constructed according to the CT data of a normal healthy adult. A femoral neck fracture model was constructed and fixed with CSs, DHSs, and the PFBN to simulate the fracture fixation model. Abaqus 6.14 software was used to compare the biomechanical characters of the three fracture fixation models. Results: The maximum stresses and displacements of the normal proximal femur were 45.35 MPa and 2.83 mm, respectively. Under axial loading, the PFBN was more effective than DHSs and CSs in improving the stress concentration of the internal fixation and reducing the peak values of von Mises stress, maximum principal stress, and minimum principal stress. The PFBN fixation model exhibits superior overall and fracture section stability in comparison to both the DHS fixation model and the CS fixation model under axial loading. Notably, the maximum stress and peak displacement of the PFBN and bone were lower than those of the DHS and CS fixation models under bending and torsional loading. Conclusion: The PFBN shows considerable improvement in reducing stress concentration, propagating stress, and enhancing the overall stability in the femoral neck fracture fixation model compared to DHSs and CSs. These enhancements more closely correspond to the tissue structure and biomechanical characteristics of the proximal femur, demonstrating that the PFBN has great potential for therapeutic purposes in treating femoral neck fractures.
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Affiliation(s)
- Kai Ding
- Hebei Orthopaedic Clinical Research Center, Department of Orthopaedic Surgery, Hebei Medical University Third Hospital, Shijiazhuang, China
- Key Laboratory of Biomechanics of Hebei Province, Orthopaedic Research Institute of Hebei Province, Shijiazhuang, Hebei, China
- NHC Key Laboratory of Intelligent Orthopeadic Equipment, Hebei Medical University Third Hospital, Shijiazhuang, China
- Engineering Research Center of Orthopaedic Minimally Invasive Intelligent Equipment, Ministry of Education, Shijiazhuang, China
| | - Yanbin Zhu
- Hebei Orthopaedic Clinical Research Center, Department of Orthopaedic Surgery, Hebei Medical University Third Hospital, Shijiazhuang, China
- Key Laboratory of Biomechanics of Hebei Province, Orthopaedic Research Institute of Hebei Province, Shijiazhuang, Hebei, China
- NHC Key Laboratory of Intelligent Orthopeadic Equipment, Hebei Medical University Third Hospital, Shijiazhuang, China
- Engineering Research Center of Orthopaedic Minimally Invasive Intelligent Equipment, Ministry of Education, Shijiazhuang, China
| | - Yifan Zhang
- Hebei Orthopaedic Clinical Research Center, Department of Orthopaedic Surgery, Hebei Medical University Third Hospital, Shijiazhuang, China
- Key Laboratory of Biomechanics of Hebei Province, Orthopaedic Research Institute of Hebei Province, Shijiazhuang, Hebei, China
- NHC Key Laboratory of Intelligent Orthopeadic Equipment, Hebei Medical University Third Hospital, Shijiazhuang, China
- Engineering Research Center of Orthopaedic Minimally Invasive Intelligent Equipment, Ministry of Education, Shijiazhuang, China
| | - Yonglong Li
- Hebei Orthopaedic Clinical Research Center, Department of Orthopaedic Surgery, Hebei Medical University Third Hospital, Shijiazhuang, China
- Key Laboratory of Biomechanics of Hebei Province, Orthopaedic Research Institute of Hebei Province, Shijiazhuang, Hebei, China
- NHC Key Laboratory of Intelligent Orthopeadic Equipment, Hebei Medical University Third Hospital, Shijiazhuang, China
- Engineering Research Center of Orthopaedic Minimally Invasive Intelligent Equipment, Ministry of Education, Shijiazhuang, China
| | - Haicheng Wang
- Hebei Orthopaedic Clinical Research Center, Department of Orthopaedic Surgery, Hebei Medical University Third Hospital, Shijiazhuang, China
- Key Laboratory of Biomechanics of Hebei Province, Orthopaedic Research Institute of Hebei Province, Shijiazhuang, Hebei, China
- NHC Key Laboratory of Intelligent Orthopeadic Equipment, Hebei Medical University Third Hospital, Shijiazhuang, China
- Engineering Research Center of Orthopaedic Minimally Invasive Intelligent Equipment, Ministry of Education, Shijiazhuang, China
| | - Jiaxing Li
- Hebei Orthopaedic Clinical Research Center, Department of Orthopaedic Surgery, Hebei Medical University Third Hospital, Shijiazhuang, China
- Key Laboratory of Biomechanics of Hebei Province, Orthopaedic Research Institute of Hebei Province, Shijiazhuang, Hebei, China
- NHC Key Laboratory of Intelligent Orthopeadic Equipment, Hebei Medical University Third Hospital, Shijiazhuang, China
- Engineering Research Center of Orthopaedic Minimally Invasive Intelligent Equipment, Ministry of Education, Shijiazhuang, China
| | - Wei Chen
- Hebei Orthopaedic Clinical Research Center, Department of Orthopaedic Surgery, Hebei Medical University Third Hospital, Shijiazhuang, China
- Key Laboratory of Biomechanics of Hebei Province, Orthopaedic Research Institute of Hebei Province, Shijiazhuang, Hebei, China
- NHC Key Laboratory of Intelligent Orthopeadic Equipment, Hebei Medical University Third Hospital, Shijiazhuang, China
- Engineering Research Center of Orthopaedic Minimally Invasive Intelligent Equipment, Ministry of Education, Shijiazhuang, China
| | - Qi Zhang
- Hebei Orthopaedic Clinical Research Center, Department of Orthopaedic Surgery, Hebei Medical University Third Hospital, Shijiazhuang, China
- Key Laboratory of Biomechanics of Hebei Province, Orthopaedic Research Institute of Hebei Province, Shijiazhuang, Hebei, China
- NHC Key Laboratory of Intelligent Orthopeadic Equipment, Hebei Medical University Third Hospital, Shijiazhuang, China
- Engineering Research Center of Orthopaedic Minimally Invasive Intelligent Equipment, Ministry of Education, Shijiazhuang, China
| | - Yingze Zhang
- Hebei Orthopaedic Clinical Research Center, Department of Orthopaedic Surgery, Hebei Medical University Third Hospital, Shijiazhuang, China
- Key Laboratory of Biomechanics of Hebei Province, Orthopaedic Research Institute of Hebei Province, Shijiazhuang, Hebei, China
- NHC Key Laboratory of Intelligent Orthopeadic Equipment, Hebei Medical University Third Hospital, Shijiazhuang, China
- Engineering Research Center of Orthopaedic Minimally Invasive Intelligent Equipment, Ministry of Education, Shijiazhuang, China
- Chinese Academy of Engineering, Bejing, China
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Zdero R, Djuricic A, Schemitsch EH. Mechanical Properties of Synthetic Bones Made by Synbone: A Review. J Biomech Eng 2023; 145:121003. [PMID: 37542709 DOI: 10.1115/1.4063123] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2023] [Accepted: 08/03/2023] [Indexed: 08/07/2023]
Abstract
Biomechanical engineers and physicists commonly employ biological bone for biomechanics studies, since they are good representations of living bone. Yet, there are challenges to using biological bone, such as cost, degradation, disease, ethics, shipping, sourcing, storage, variability, etc. Therefore, the Synbone® company has developed a series of synthetic bones that have been used by biomechanical investigators to offset some drawbacks of biological bone. There have been a number of published biomechanical reports using these bone surrogates for dental, injury, orthopedic, and other applications. But, there is no prior review paper that has summarized the mechanical properties of these synthetic bones in order to understand their general performance or how well they represent biological bone. Thus, the goal of this article was to survey the English-language literature on the mechanical properties of these synthetic bones. Studies were included if they quantitatively (a) characterized previously unknown values for synthetic bone, (b) validated synthetic versus biological bone, and/or (c) optimized synthetic bone performance by varying geometric or material parameters. This review of data, pros, cons, and future work will hopefully assist biomechanical engineers and physicists that use these synthetic bones as they develop experimental testing regimes and computational models.
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Affiliation(s)
- Radovan Zdero
- Orthopaedic Biomechanics Lab, Victoria Hospital, London, ON N6A-5W9, Canada
| | - Aleksandar Djuricic
- Orthopaedic Biomechanics Lab, Victoria Hospital, Room A6-144, 800 Commissioners Road East, London, ON N6A-5W9, Canada
| | - Emil H Schemitsch
- Orthopaedic Biomechanics Lab, Victoria Hospital, London, ON N6A-5W9, Canada; Division of Orthopaedic Surgery, Western University, London, ON N6A-5A5, Canada
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20
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Yun C, Qian W, Zhang J, Zhang W, Lv J. Biomechanics of PHILOS plates in Vancouver B1 periprosthetic femoral fracture. Front Bioeng Biotechnol 2023; 11:1282128. [PMID: 38047287 PMCID: PMC10690819 DOI: 10.3389/fbioe.2023.1282128] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2023] [Accepted: 11/08/2023] [Indexed: 12/05/2023] Open
Abstract
Objective: To investigate the clinical efficacy of PHILOS plates in the treatment of Vancouver B1 periprosthetic femoral fracture (PFF) and to validate its biomechanical reliability via finite element analysis and mechanical testing on the Synbone femoral models. Methods: Ten males and eight females with Vancouver B1 PFF who underwent PHILOS plate fixation between September 2017 and January 2022 were selected. The average age was 72.61 ± 8.19 years, with a range of 57-86 years old. X-ray films were taken to assess the fracture healing situation around the femoral prosthesis as well as the position of the PHILOS plates and femoral prosthesis. Two different plates (the PHILOS plate and the Cable GTR plate) were used for fixation, and the differences in biomechanical stability of the two fixation methods were compared using finite element analysis and mechanical testing on the Synbone femoral models to validate the biomechanical dependability of the PHILOS plate. Results: All 18 cases were followed for at least 1 year, as a result. The average period of follow-up was 17 months, ranging from 12 to 36 months. At the most recent follow-up, Harris scores for the hip joints of patients ranged from 82 to 89, with an average score of 86. The X-rays revealed that all fractures surrounding the femoral prosthesis had healed and that there was no looseness in the femoral prosthesis. None of the PHILOS license plates had expired. All patients were able to perform full-load walking, and pain and claudication in affected limbs were significantly reduced. Finite element analysis and mechanical testing of the Synbone femoral model revealed that the fixation effect of the PHILOS group was superior to that of the Cable group; consequently, PHILOS plates can be used to effectively fix fractures around the proximal femoral prosthesis. Conclusion: PHILOS plates are initially used in the treatment of Vancouver B1 PFF, which may be a good choice due to their simpler operation, lower medical costs, and satisfactory clinical efficacy.
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Affiliation(s)
- Changjun Yun
- Departmeut of Orthopaedics, The Affiliated Wujin Hospital of Jiangsu University, Changzhou, China
- The Wujin Clinical College of Xuzhou Medical University, Changzhou, China
| | - Wenjie Qian
- Departmeut of Orthopaedics, The Affiliated Wujin Hospital of Jiangsu University, Changzhou, China
- The Wujin Clinical College of Xuzhou Medical University, Changzhou, China
| | - Jie Zhang
- Departmeut of Orthopaedics, The Affiliated Wujin Hospital of Jiangsu University, Changzhou, China
- The Wujin Clinical College of Xuzhou Medical University, Changzhou, China
| | - Wen Zhang
- Orthopedic Institute, Soochow University, Suzhou, China
| | - Jinpeng Lv
- School of Pharmacy, Changzhou University, Changzhou, China
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21
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Chen P, Fan Z, Xu N, Wang H. A biomechanical investigation of a novel intramedullary nail used to salvage failed internal fixations in intertrochanteric fractures. J Orthop Surg Res 2023; 18:632. [PMID: 37641046 PMCID: PMC10463605 DOI: 10.1186/s13018-023-04112-w] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/12/2023] [Accepted: 08/17/2023] [Indexed: 08/31/2023] Open
Abstract
PURPOSE The ideal approach for revision surgery following femoral head salvage treatments for an intertrochanteric fracture is still up for debate. A novel variety of proximal femoral bionic intramedullary nail (PFBN) has been created in clinical practice. We aimed to compare the biomechanical results of the novel implant to conventional intramedullary and extramedullary fixation in the treatment of intertrochanteric fracture following primary internal fixation failure. METHODS Using finite element analysis, we created a three-dimensional model of the intertrochanteric fracture's helical blade cut-out for this investigation. The PFBN 1 group, the PFBN 2 group, the PFNA group, and the DHS group were our four test groups. For each fracture group, the von Mises stress and displacements of the femur and internal fixation components were measured under 2100 N axial loads. RESULTS The values for the femoral displacement in the PFBN1 group, PFBN2 group, PFNA group, and DHS group were 6.802 mm, 6.716 mm, 8.080 mm, and 8.679 mm, respectively. The internal implant displacement values were 6.201 mm, 6.138 mm, 7.396 mm, and 8.075 mm in the PFBN1 group, PFBN2 group, PFNA group, and DHS group, respectively. The maximum von Mises Stress in the femoral was 187.2 MPa, 85.18 MPa, 106.6 MPa, and 386.2 MPa in the PFBN1 groups, PFBN2 groups, PFNA groups, and DHS groups, respectively. In the PFBN1 groups, PFBN2 groups, PFNA groups, and DHS groups, the maximum von Mises Stress in internal fixation was 586.7 MPa, 559.8 MPa, 370.7 MPa, and 928.4.8 MPa, respectively. CONCLUSION Our biomechanical research demonstrates that intramedullary fixation is more stable than extramedullary fixation when salvaging failed internal fixations in intertrochanteric fracture. Compared with PFNA and DHS, PFBN showed better biomechanical stability in the treatment of patients with revised intertrochanteric fractures. In light of this, we advocate PFBN fixation as the method of choice for intertrochanteric fracture revision. This result still has to be confirmed in more clinical research.
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Affiliation(s)
- Ping Chen
- The Second Affiliated Hospital of Guangzhou University of Traditional Chinese Medicine (Guangdong Provincial Hospital of Traditional Chinese Medicine), Guangzhou University of Chinese Medicine, Guangzhou, 510120, China
| | - Zhirong Fan
- The Second Affiliated Hospital of Guangzhou University of Traditional Chinese Medicine (Guangdong Provincial Hospital of Traditional Chinese Medicine), Guangzhou University of Chinese Medicine, Guangzhou, 510120, China
| | - Nengneng Xu
- Panyu Hospital of Chinese Medicine, Guangzhou University of Chinese Medicine, Guangzhou, 511401, China
| | - Haizhou Wang
- The Second Affiliated Hospital of Guangzhou University of Traditional Chinese Medicine (Guangdong Provincial Hospital of Traditional Chinese Medicine), Guangzhou University of Chinese Medicine, Guangzhou, 510120, China.
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22
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Zdero R, Brzozowski P, Schemitsch EH. Biomechanical properties of artificial bones made by Sawbones: A review. Med Eng Phys 2023; 118:104017. [PMID: 37536838 DOI: 10.1016/j.medengphy.2023.104017] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2023] [Revised: 06/23/2023] [Accepted: 06/27/2023] [Indexed: 08/05/2023]
Abstract
Biomedical engineers and physicists frequently use human or animal bone for orthopaedic biomechanics research because they are excellent approximations of living bone. But, there are drawbacks to biological bone, like degradation over time, ethical concerns, high financial costs, inter-specimen variability, storage requirements, supplier sourcing, transportation rules, etc. Consequently, since the late 1980s, the Sawbones® company has been one of the world's largest suppliers of artificial bones for biomechanical testing that counteract many disadvantages of biological bone. There have been many published reports using these bone analogs for research on joint replacement, bone fracture fixation, spine surgery, etc. But, there exists no prior review paper on these artificial bones that gives a comprehensive and in-depth look at the numerical data of interest to biomedical engineers and physicists. Thus, this paper critically reviews 25 years of English-language studies on the biomechanical properties of these artificial bones that (a) characterized unknown or unreported values, (b) validated them against biological bone, and/or (c) optimized different design parameters. This survey of data, advantages, disadvantages, and knowledge gaps will hopefully be useful to biomedical engineers and physicists in developing mechanical testing protocols and computational finite element models.
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Affiliation(s)
- Radovan Zdero
- Orthopaedic Biomechanics Lab, Victoria Hospital, London, ON, Canada
| | - Pawel Brzozowski
- Orthopaedic Biomechanics Lab, Victoria Hospital, London, ON, Canada.
| | - Emil H Schemitsch
- Orthopaedic Biomechanics Lab, Victoria Hospital, London, ON, Canada; Division of Orthopaedic Surgery, Western University, London, ON, Canada
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23
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Ceddia M, Trentadue B. Evaluation of Rotational Stability and Stress Shielding of a Stem Optimized for Hip Replacements—A Finite Element Study. PROSTHESIS 2023; 5:678-693. [DOI: 10.3390/prosthesis5030048] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/03/2025]
Abstract
The natural distribution of stress in the femur is altered when total hip arthroplasty (THA) is performed. In fact, when a stem is inserted inside the femur, there is a variation in stress due to the difference in rigidity between the material with which the stem is made and the femur. This generates the phenomenon of stress shielding. The aim of this study is to design an optimized prosthesis that guarantees an excellent rotational stability and a reduced stress shielding. Methods: Through the finite element method (FEM), the mechanical behavior of the stem subjected to the loads described by ISO 7206-4:2010 is studied. Results: Through topological optimization, there is a reduction in stress shielding in the proximal zone of 31.46%. The addition of ridges on the dorsal side of the stem also improves rotational stability by 27.82%. Conclusions: The decrease in stiffness that is recorded with the optimized stem guarantees a greater distribution of stress on the bone. The presence of dorsal ridges also favors the corticalization of the bone as it loads the bone near the dorsal, ensuring further stability. The perforated prosthesis presented in this study shows an increase in primary stability and an improvement in rotational stability as there is also a bone regrowth inside the prosthesis.
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Affiliation(s)
- Mario Ceddia
- Department of Mechanics, Mathematics and Management, Politecnico di Bari University, 70125 Bari, Italy
| | - Bartolomeo Trentadue
- Department of Mechanics, Mathematics and Management, Politecnico di Bari University, 70125 Bari, Italy
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Wisanuyotin T, Paholpak P, Sirichativapee W, Sirichativapee W, Kosuwon W. Effect of bone cement augmentation with different configurations of the dual locking plate for femoral allograft fixation: finite element analysis and biomechanical study. J Orthop Surg Res 2023; 18:405. [PMID: 37270556 DOI: 10.1186/s13018-023-03894-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/25/2023] [Accepted: 05/30/2023] [Indexed: 06/05/2023] Open
Abstract
AIMS Implant failure in allograft reconstruction is one of the most common problems after treating a large bone defect for a primary bone tumor. The study aimed to investigate the effect of bone cement augmentation with different configurations of dual locking plates used for femoral allograft fixation. METHODS Four finite element (FE) models of the femur with a 1-mm bone gap were developed at the midshaft with different configurations of the 10-hole fixation dual locking plate (LP) with and without intramedullary bone cement augmentation. Model 1 was the dual LP at the lateral and medial aspect of the femur. Model 2 was Model 1 with bone cement augmentation. Model 3 was the dual LP at the anterior and lateral aspect of the femur. Finally, Model 4 was Model 3 with bone cement augmentation. All models were tested for stiffness under axial compression as well as torsional, lateral-medial, and anterior-posterior bending. In addition, the FE analyses were validated using biomechanical testing on a cadaveric femur. RESULTS Model 2 had the greatest axial compression stiffness, followed by Models 1, 4, and 3. Bone cement augmentation in Models 2 and 4 had 3.5% and 2.4% greater axial stiffness than the non-augmentation Models 1 and 3, respectively. In the bone cement augmentation models, Model 2 had 11.9% greater axial compression stiffness than Model 4. CONCLUSION The effect of bone cement augmentation increases construct stiffness less than the effect of the dual LP configuration. A dual lateral-medial LP with bone cement augmentation provides the strongest fixation of the femur in terms of axial compression and lateral bending stiffness.
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Affiliation(s)
- Taweechok Wisanuyotin
- Department of Orthopaedics, Faculty of Medicine, Khon Kaen University, Khon Kaen, 40002, Thailand.
| | - Permsak Paholpak
- Department of Orthopaedics, Faculty of Medicine, Khon Kaen University, Khon Kaen, 40002, Thailand
| | - Winai Sirichativapee
- Department of Orthopaedics, Faculty of Medicine, Khon Kaen University, Khon Kaen, 40002, Thailand
| | - Wilasinee Sirichativapee
- Department of Orthopaedics, Faculty of Medicine, Khon Kaen University, Khon Kaen, 40002, Thailand
| | - Weerachai Kosuwon
- Department of Orthopaedics, Faculty of Medicine, Khon Kaen University, Khon Kaen, 40002, Thailand
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25
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Glatt V, O'Toole R, Mehta S, Kandemir U, Ricci W, Nauth A, Schemitsch E, Hast MW. Great debates in trauma biomechanics. OTA Int 2023; 6:e249. [PMID: 37168029 PMCID: PMC10166369 DOI: 10.1097/oi9.0000000000000249] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2022] [Accepted: 12/22/2022] [Indexed: 05/13/2023]
Abstract
At the 2021 annual meeting of the Orthopaedic Trauma Association, the Basic Science Focus Forum hosted its first ever debate-style symposium focused on biomechanics and fracture repair. The 3 subjects of debate were "Mechanics versus Biology-Which is 'More Important' to Consider?" "Locked Plate versus Forward Dynamization versus Reverse Dynamization-Which Way Should I Go?" and "Sawbones versus Cadaver Models-What Should I Believe Most?" These debates were held because fracture healing is a highly organized synergistic response between biological factors and the local mechanical environment. Multiple studies have demonstrated that both factors play roles in governing bone healing responses, and the causal relationships between the 2 remain unclear. The lack of clarity in this space has led to a spectrum of research with the common goal of helping surgeons make good decisions. Before reading further, the reader should understand that the questions posed in the debate titles are unanswerable and might represent a false choice. Instead, the reader should appreciate that the debates were held to gain a more thorough understanding of these topics based on the current state of the art of experimental and clinical studies, by using an engaging and thought-provoking format.
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Affiliation(s)
- Vaida Glatt
- Department of Orthopaedic Surgery, University of Texas Health Science Center San Antonio, San Antonio, TX
| | - Robert O'Toole
- Department of Orthopaedic Surgery, University of Maryland Medical System, Baltimore, MD
| | - Samir Mehta
- Department of Orthopaedic Surgery, University of Pennsylvania, Philadelphia, PA
| | - Utku Kandemir
- Department of Orthopaedic Surgery, University of California, San Francisco, San Francisco, CA
| | - William Ricci
- Department of Orthopaedic Surgery, Hospital for Special Surgery and New York Presbyterian Hospital, New York, NY
| | - Aaron Nauth
- Department of Orthopaedic Surgery, University of Toronto, Toronto, ON, Canada; and
| | - Emil Schemitsch
- Department of Orthopaedic Surgery, Western University, London, ON, Canada
| | - Michael W. Hast
- Department of Orthopaedic Surgery, University of Pennsylvania, Philadelphia, PA
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Naghavi SA, Tamaddon M, Garcia-Souto P, Moazen M, Taylor S, Hua J, Liu C. A novel hybrid design and modelling of a customised graded Ti-6Al-4V porous hip implant to reduce stress-shielding: An experimental and numerical analysis. Front Bioeng Biotechnol 2023; 11:1092361. [PMID: 36777247 PMCID: PMC9910359 DOI: 10.3389/fbioe.2023.1092361] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2022] [Accepted: 01/10/2023] [Indexed: 01/27/2023] Open
Abstract
Stress shielding secondary to bone resorption is one of the main causes of aseptic loosening, which limits the lifespan of hip prostheses and exacerbates revision surgery rates. In order to minimise post-hip replacement stress variations, this investigation proposes a low-stiffness, porous Ti6Al4V hip prosthesis, developed through selective laser melting (SLM). The stress shielding effect and potential bone resorption properties of the porous hip implant were investigated through both in vitro quasi-physiological experimental assays, together with finite element analysis. A solid hip implant was incorporated in this investigation for contrast, as a control group. The stiffness and fatigue properties of both the solid and the porous hip implants were measured through compression tests. The safety factor of the porous hip stem under both static and dynamic loading patterns was obtained through simulation. The porous hip implant was inserted into Sawbone/PMMA cement and was loaded to 2,300 N (compression). The proposed porous hip implant demonstrated a more natural stress distribution, with reduced stress shielding (by 70%) and loss in bone mass (by 60%), when compared to a fully solid hip implant. Solid and porous hip stems had a stiffness of 2.76 kN/mm and 2.15 kN/mm respectively. Considering all daily activities, the porous hip stem had a factor of safety greater than 2. At the 2,300 N load, maximum von Mises stresses on the hip stem were observed as 112 MPa on the medial neck and 290 MPa on the distal restriction point, whereby such values remained below the endurance limit of 3D printed Ti6Al4V (375 MPa). Overall, through the strut thickness optimisation process for a Ti6Al4V porous hip stem, stress shielding and bone resorption can be reduced, therefore proposing a potential replacement for the generic solid implant.
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Affiliation(s)
- Seyed Ataollah Naghavi
- Institute of Orthopaedics and Musculoskeletal Science, Division of Surgery and Interventional Science, Royal National Orthopaedic Hospital, University College London, Stanmore, United Kingdom
| | - Maryam Tamaddon
- Institute of Orthopaedics and Musculoskeletal Science, Division of Surgery and Interventional Science, Royal National Orthopaedic Hospital, University College London, Stanmore, United Kingdom
| | - Pilar Garcia-Souto
- Medical Physics and Biomedical Engineering, University College London, London, United Kingdom
| | - Mehran Moazen
- Department of Mechanical Engineering, University College London, London, United Kingdom
| | - Stephen Taylor
- Institute of Orthopaedics and Musculoskeletal Science, Division of Surgery and Interventional Science, Royal National Orthopaedic Hospital, University College London, Stanmore, United Kingdom
| | - Jia Hua
- School of Science and Technology, Middlesex University, London, United Kingdom
| | - Chaozong Liu
- Institute of Orthopaedics and Musculoskeletal Science, Division of Surgery and Interventional Science, Royal National Orthopaedic Hospital, University College London, Stanmore, United Kingdom,*Correspondence: Chaozong Liu,
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Effective Treatment of Femur Diaphyseal Fracture with Compression Plate - A Finite Element and In Vivo Study Comparing the Healing Outcomes of Nailing and Plating. Indian J Orthop 2022; 57:146-158. [PMID: 36660487 PMCID: PMC9789296 DOI: 10.1007/s43465-022-00795-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/30/2022] [Accepted: 11/07/2022] [Indexed: 12/14/2022]
Abstract
BACKGROUND The rigidity in osteosynthesis causes primary healing, and it takes longer to heal. The flexibility provided to the fixation allows micromotion between fragments which accelerates secondary healing. METHODS In this study, the healing outcomes of nailing and plating in different fixation stabilities were investigated and compared by using a finite element tool. The clinical observational study was also performed to verify the results of the finite element analysis. The nonlinear contact analysis was performed on 5 different fixation configurations capturing nail and plate in immediate post-surgery. RESULTS The finite element analysis results showed that flexibility instead of rigidity in interlock nail implantation increases the axial and shear micromotion near the fracture site by 47.4% (P < 0.05) and 12.4% (P < 0.05), respectively. For LCDCP implantation, the flexible fixation increases the axial and shear micromotion near fracture site by 75.7% (P < 0.05) and 25.3% (P < 0.05), respectively. CONCLUSION Our findings suggest that flexible fixations of interlock nail and LCDCP provide a preferred mechanical environment for healing, and hence, the LCDCP in flexible mode can be an effective alternative to interlock nail for the femur diaphyseal fracture. SUPPLEMENTARY INFORMATION The online version contains supplementary material available at 10.1007/s43465-022-00795-1.
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Nägl K, Reisinger A, Pahr DH. The biomechanical behavior of 3D printed human femoral bones based on generic and patient-specific geometries. 3D Print Med 2022; 8:35. [PMID: 36418789 PMCID: PMC9685985 DOI: 10.1186/s41205-022-00162-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2022] [Accepted: 10/18/2022] [Indexed: 11/25/2022] Open
Abstract
BACKGROUND Bone is a highly complex composite material which makes it hard to find appropriate artificial surrogates for patient-specific biomechanical testing. Despite various options of commercially available bones with generic geometries, these are either biomechanically not very realistic or rather expensive. METHODS In this work, additive manufacturing was used for the fabrication of artificial femoral bones. These were based on CT images of four different commercially available femoral bone surrogates and three human bones with varying bone density. The models were 3D printed using a low-budget fused deposition modeling (FDM) 3D printer and PLA filament. The infill density was mechanically calibrated and varying cortical thickness was used. Compression tests of proximal femora simulating stance were performed and the biomechanical behavior concerning ultimate force, spring stiffness, and fracture pattern were evaluated as well as compared to the results of commercial and cadaveric bones. RESULTS Regarding the ultimate forces and spring stiffness, the 3D printed analogs showed mechanical behavior closer to their real counterparts than the commercially available polyurethan-based surrogates. Furthermore, the increase in ultimate force with increasing bone density observed in human femoral bones could be reproduced well. Also, the fracture patterns observed match well with fracture patterns observed in human hip injuries. CONCLUSION Consequently, the methods presented here show to be a promising alternative for artificial generic surrogates concerning femoral strength testing. The manufacturing is straightforward, cheap, and patient-specific geometries are possible.
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Affiliation(s)
- Katharina Nägl
- Division Biomechanics, Karl Landsteiner University of Health Science, Dr.-Karl-Dorrek-Straße 30, 3500, Krems an der Donau, Austria
- Institute for Lightweight Design and Structural Biomechanics, TU Wien, Getreidemarkt 9, 1060, Wien, Austria
| | - Andreas Reisinger
- Division Biomechanics, Karl Landsteiner University of Health Science, Dr.-Karl-Dorrek-Straße 30, 3500, Krems an der Donau, Austria
- Institute for Lightweight Design and Structural Biomechanics, TU Wien, Getreidemarkt 9, 1060, Wien, Austria
| | - Dieter H Pahr
- Division Biomechanics, Karl Landsteiner University of Health Science, Dr.-Karl-Dorrek-Straße 30, 3500, Krems an der Donau, Austria.
- Institute for Lightweight Design and Structural Biomechanics, TU Wien, Getreidemarkt 9, 1060, Wien, Austria.
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Naghavi SA, Lin C, Sun C, Tamaddon M, Basiouny M, Garcia-Souto P, Taylor S, Hua J, Li D, Wang L, Liu C. Stress Shielding and Bone Resorption of Press-Fit Polyether-Ether-Ketone (PEEK) Hip Prosthesis: A Sawbone Model Study. Polymers (Basel) 2022; 14:4600. [PMID: 36365594 PMCID: PMC9657056 DOI: 10.3390/polym14214600] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2022] [Revised: 10/22/2022] [Accepted: 10/25/2022] [Indexed: 09/23/2023] Open
Abstract
Stress shielding secondary to bone resorption is one of the main causes of aseptic loosening, which limits the lifespan of the hip prostheses and increases the rates of revision surgery. This study proposes a low stiffness polyether-ether-ketone (PEEK) hip prostheses, produced by fused deposition modelling to minimize the stress difference after the hip replacement. The stress shielding effect and the potential bone resorption of the PEEK implant was investigated through both experimental tests and FE simulation. A generic Ti6Al4V implant was incorporated in this study to allow fair comparison as control group. Attributed to the low stiffness, the proposed PEEK implant showed a more natural stress distribution, less stress shielding (by 104%), and loss in bone mass (by 72%) compared with the Ti6Al4V implant. The stiffness of the Ti6Al4V and the PEEK implant were measured through compression tests to be 2.76 kN/mm and 0.276 kN/mm. The factor of safety for the PEEK implant in both static and dynamic loading scenarios were obtained through simulation. Most of the regions in the PEEK implant were tested to be safe (FoS larger than 1) in terms of representing daily activities (2300 N), while the medial neck and distal restriction point of the implant attracts large von Mises stress 82 MPa and 76 MPa, respectively, and, thus, may possibly fail during intensive activities by yield and fatigue. Overall, considering the reduction in stress shielding and bone resorption in cortical bone, PEEK could be a promising material for the patient-specific femoral implants.
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Affiliation(s)
- Seyed Ataollah Naghavi
- Institute of Orthopaedics & Musculoskeletal Science, Division of Surgery & Interventional Science, University College London, Royal National Orthopaedic Hospital, Stanmore, London HA7 4LP, UK
| | - Churun Lin
- Department of Mechanical Engineering, University College London, London WC1E 7JE, UK
| | - Changning Sun
- Institute of Orthopaedics & Musculoskeletal Science, Division of Surgery & Interventional Science, University College London, Royal National Orthopaedic Hospital, Stanmore, London HA7 4LP, UK
- State Key Laboratory for Manufacturing Systems Engineering, School of Mechanical Engineering, Xi’an Jiaotong University, Xi’an 710049, China
- National Medical Products Administration (NMPA), Key Laboratory for Research and Evaluation of Additive Manufacturing Medical Devices, Xi’an Jiaotong University, Xi’an 710054, China
| | - Maryam Tamaddon
- Institute of Orthopaedics & Musculoskeletal Science, Division of Surgery & Interventional Science, University College London, Royal National Orthopaedic Hospital, Stanmore, London HA7 4LP, UK
| | - Mariam Basiouny
- Institute of Orthopaedics & Musculoskeletal Science, Division of Surgery & Interventional Science, University College London, Royal National Orthopaedic Hospital, Stanmore, London HA7 4LP, UK
| | - Pilar Garcia-Souto
- Medical Physics & Biomedical Engineering, University College London, London WC1E 6BT, UK
| | - Stephen Taylor
- Institute of Orthopaedics & Musculoskeletal Science, Division of Surgery & Interventional Science, University College London, Royal National Orthopaedic Hospital, Stanmore, London HA7 4LP, UK
| | - Jia Hua
- School of Science and Technology, Middlesex University, London NW4 4BT, UK
| | - Dichen Li
- State Key Laboratory for Manufacturing Systems Engineering, School of Mechanical Engineering, Xi’an Jiaotong University, Xi’an 710049, China
- National Medical Products Administration (NMPA), Key Laboratory for Research and Evaluation of Additive Manufacturing Medical Devices, Xi’an Jiaotong University, Xi’an 710054, China
| | - Ling Wang
- State Key Laboratory for Manufacturing Systems Engineering, School of Mechanical Engineering, Xi’an Jiaotong University, Xi’an 710049, China
- National Medical Products Administration (NMPA), Key Laboratory for Research and Evaluation of Additive Manufacturing Medical Devices, Xi’an Jiaotong University, Xi’an 710054, China
| | - Chaozong Liu
- Institute of Orthopaedics & Musculoskeletal Science, Division of Surgery & Interventional Science, University College London, Royal National Orthopaedic Hospital, Stanmore, London HA7 4LP, UK
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Sun H, Zhang H, Wang T, Zheng K, Zhang W, Li W, Zhang W, Xu Y, Geng D. Biomechanical and Finite-Element Analysis of Femoral Pin-Site Fractures Following Navigation-Assisted Total Knee Arthroplasty. J Bone Joint Surg Am 2022; 104:1738-1749. [PMID: 36197326 DOI: 10.2106/jbjs.21.01496] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
BACKGROUND Femoral pin-site fracture is one of the most serious complications of navigation-assisted total knee arthroplasty (TKA). Its occurrence is associated with the loss of biomechanical strength caused by intraoperative femoral drilling. This study aimed to investigate the drilling location as a risk factor for pin-site fracture. METHODS A biomechanical analysis using rabbit femora was performed to determine the effects of drilling eccentricity and height. Torsional, 3-point bending, and axial compression tests were performed to evaluate biomechanical parameters, including failure strength, failure displacement, and stiffness. Fracture type and the presence of comminution were noted and analyzed. Finite-element analysis (FEA) was utilized to assess the stress distribution and deformation. The cumulative sum (CUSUM) method was applied to define the safe range for drilling eccentricity. RESULTS Drilling operations were accurately implemented. Biomechanical tests confirmed that severely eccentric drilling significantly reduced the biomechanical strength of the femur, especially in torsion. FEA results provided evidence of threatening stress concentration in severely eccentric drilling. The overall safe range of eccentricity relative to the center of the femur was found to be between 50% of the radius in the anterolateral direction and 70% of the radius in the posteromedial direction. CONCLUSIONS Severely eccentric drilling significantly increased the risk of femoral pin-site fracture, especially under torsional stress. Femoral drilling should be performed in the safe zone that was identified.
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Affiliation(s)
- Houyi Sun
- Department of Orthopedics, The First Affiliated Hospital of Soochow University, Suzhou, People's Republic of China.,Department of Orthopedics, Qilu Hospital of Shandong University, Jinan, People's Republic of China
| | - Haifeng Zhang
- Department of Orthopedics, The First Affiliated Hospital of Soochow University, Suzhou, People's Republic of China
| | - Tianhao Wang
- Department of Orthopedics, The First Affiliated Hospital of Soochow University, Suzhou, People's Republic of China
| | - Kai Zheng
- Department of Orthopedics, The First Affiliated Hospital of Soochow University, Suzhou, People's Republic of China
| | - Weicheng Zhang
- Department of Orthopedics, The First Affiliated Hospital of Soochow University, Suzhou, People's Republic of China
| | - Wenming Li
- Department of Orthopedics, The First Affiliated Hospital of Soochow University, Suzhou, People's Republic of China
| | - Wen Zhang
- Orthopedic Institute, Soochow University, Suzhou, People's Republic of China
| | - Yaozeng Xu
- Department of Orthopedics, The First Affiliated Hospital of Soochow University, Suzhou, People's Republic of China
| | - Dechun Geng
- Department of Orthopedics, The First Affiliated Hospital of Soochow University, Suzhou, People's Republic of China
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Investigation of the process intergrowth of bone tissue into the hole in titanium implants (Experimental research). Injury 2022; 53:2741-2748. [PMID: 35667886 DOI: 10.1016/j.injury.2022.05.007] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/17/2021] [Revised: 04/19/2022] [Accepted: 05/10/2022] [Indexed: 02/02/2023]
Abstract
INTRODUCTION Despite the use of modern implants, complications such as nonunion and avascular necrosis of the femoral head are observed in femoral neck fractures (FNF). We have created a new perforated I-beam implant for FNF osteosynthesis and developed a new osteosynthesis philosophy based not only on the mechanical and biomechanical interaction of the bone-implant system, but also on the interaction of the biological properties of the bone and the implant. The purpose of the work is to study the interaction of the biological process of the bone - its regeneration (germination) of bone tissue into the holes of the implant. MATERIALS AND METHODS The experiment was carried out on fourteen Chinchilla rabbits in accordance with all international standards. A perforated implant specially made of titanium (ChM, Poland) was surgically implanted into the proximal femur. The implant measurements were as follows: length - 6 mm, width - 3 mm, thickness - 2 mm, 2 holes with a diameter of 2 mm. The 14 rabbits were divided into 7 groups. After 1, 2, 3, 4, 5, 10 and 12 weeks the animals were withdrawn from the experiment according to the standard rules in sequential order. The preparations were placed in a formalin solution and sent to the pathomorphology laboratory (CITO, Russia) for histological studies. RESULTS Weekly histopathological studies revealed a gradual transition from the organization of a hematoma to the formation of mature bone tissue in the holes of the implants. The titanium implant is bioinert and did not cause any visible reactions from the bone tissue. Simultaneous integration of vascular proliferation and newly formed bone tissue into the implant holes were revealed. On 10-12-week preparations, the formation of trabecular structures of mature bone tissue was revealed in the holes of the implants and elements of adipose and bone marrow tissue were observed. Macroscopic examination of 4-5-week preparations showed almost complete filling of the holes with bone tissue. On 10-12-week preparations, the bone tissue in the holes of the implants did not differ from the bone tissue surrounding the implant. The processes of formation of mature bone tissue in the holes of the implants were similar to the processes of physiological bone healing (regeneration) at the fracture site. CONCLUSIONS The obtained results show the following: 1.The titanium implant is bioinert and does not cause any visible reactions from the bone tissue; 2. There is a gradual process of formation of new vessels, and then the formation of new bone tissue in the holes of the implant instead of the one damaged during implantation. Thus, the results of this experiment indirectly confirm our assumption that a perforated implant for FNF osteosynthesis will participate not only in the mechanical and biomechanical interaction of the bone-implant system, but will also include the 3rd element in this system - the biological properties of the bone itself. We assume that these properties of the new implant will increase blood flow in the femoral neck and partially replenish the volume of bone tissue destroyed during osteosynthesis which does not occur with FNF osteosynthesis by any of the known implants.
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Wang Z, Yang Y, Feng G, Guo H, Chen Z, Chen Y, Jin Q. Biomechanical comparison of the femoral neck system versus InterTan nail and three cannulated screws for unstable Pauwels type III femoral neck fracture. Biomed Eng Online 2022; 21:34. [PMID: 35689282 PMCID: PMC9188240 DOI: 10.1186/s12938-022-01006-6] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2021] [Accepted: 05/26/2022] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND There are a variety of internal fixation methods for unstable femoral neck fractures (FNFs), but the best method is still unclear. Femoral neck system (FNS) is a dynamic angular stabilization system with cross screws, and is a new internal fixation implant designed for minimally invasive fixation of FNFs. In this study, we conducted a biomechanical comparison of FNS, InterTan nail and three cannulated screws for the treatment of Pauwels III FNFs and investigate the biomechanical properties of FNS. METHODS A total of 18 left artificial femurs were selected and randomly divide into Group A (fixation with FNS), Group B (fixation with InterTan nail) and Group C (fixation with three cannulated screws), with 6 specimens in each group. After creating Pauwels type III FNF models, the specimens in each were tested with non-destructive quasi-static tests, including torsion, A-P bending and axial compression tests. The average slope of the linear load-deformation curve obtained from quasi-static tests defines the initial torsional stiffness, A-P bending stiffness, and axial compression stiffness. After cyclic loading test was applied, the overall deformation of models and local deformation of implant holes in each group were assessed. The overall deformation was estimated as the displacement recorded by the software of the mechanical testing apparatus. Local deformation was defined as interfragmental displacement. Data were analyzed by one-way analysis of variance (ANOVA) followed by Bonferroni post hoc test using the SPSS software (version 24.0, IBM, New York, NY, USA). Correlation analysis was performed using Pearson's correlation analysis. RESULTS Group B exhibited significantly higher axial stiffness and A-P bending stiffness than the other two groups (P < 0.01), while Group A had significantly higher axial stiffness and A-P bending stiffness than Group C (P < 0.01). Groups A and B exhibited significantly higher torsional stiffness than Group C (P < 0.01), no statistical significance was observed between Groups A and B (P > 0.05). Group B exhibited significantly lower overall and local deformations than the other two groups (P < 0.01), while Group A had significantly lower overall and local deformations than Group C (P < 0.01). Correlation analysis revealed positive correlation between axial stiffness and A-P bending stiffness (r = 0.925, P < 0.01), torsional stiffness (r = 0.727, P < 0.01), between torsional stiffness and A-P bending stiffness; negative correlation between overall, local deformations and axial stiffness (r = - 0.889, - 0.901, respectively, both P < 0.01), and positive correlation between the two deformations (r = - 0.978, P < 0.01). CONCLUSION For fixation of unstable FNFs, InterTan nail showed the highest axial stiffness and A-P bending stiffness, followed by FNS, and then three cannulated screws. Torsional stiffness of FNS was comparable to that of the InterTan nail. FNS, as a novel minimally invasive implant, can create good mechanical environment for the healing of unstable FNFs. Clinical studies are needed to confirm the potential advantages of FNS observed in this biomechanical study.
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Affiliation(s)
- Zheng Wang
- Department of Orthopaedic, General Hospital of Ningxia Medical University, Yinchuan, 750004, Ningxia, China
| | - Yong Yang
- Department of Orthopaedic, General Hospital of Ningxia Medical University, Yinchuan, 750004, Ningxia, China
| | - Gangning Feng
- Department of Orthopaedic, General Hospital of Ningxia Medical University, Yinchuan, 750004, Ningxia, China
| | - Haohui Guo
- Department of Orthopaedic, General Hospital of Ningxia Medical University, Yinchuan, 750004, Ningxia, China
| | - Zhirong Chen
- Department of Orthopaedic, General Hospital of Ningxia Medical University, Yinchuan, 750004, Ningxia, China
| | - Yaogeng Chen
- Ningxia Medical University, Yinchuan, 750004, Ningxia, China
| | - Qunhua Jin
- Department of Orthopaedic, General Hospital of Ningxia Medical University, Yinchuan, 750004, Ningxia, China.
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Long Y, Qi Y, Zuo G, Zhang Q, Liu Z, Wang W. Femoral periprosthetic fracture treatment using the Ortho-Bridge System: a biomechanical study. J Orthop Surg Res 2022; 17:301. [PMID: 35659004 PMCID: PMC9166506 DOI: 10.1186/s13018-022-03154-w] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/21/2021] [Accepted: 05/03/2022] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND We undertook a comparative biomechanical study of type B1 fractures around femoral prostheses following cemented hip arthroplasty using the Ortho-Bridge System (OBS) and a locking compression plate/locking attachment plate structure (LCP + LAP). We aimed to investigate the biomechanical characteristics and advantages of the OBS compared with LCP + LAP when treating this fracture type. METHODS An OBS fixation model was designed based on OBS and LCP + LAP fixation characteristics. The LCP + LAP combination (Group A) and three different OBS combinations (Groups B, C, and D) were used to fix a B1 fracture model with a femoral periprosthetic fracture. Axial compression and torsion experiments were then performed using simple and comminuted fracture models. The axial compression failure experiment was carried out, and the model stiffness during axial compression, torsion angle in torsion test, and vertical load in the final failure test were collected. RESULTS When simulating simple oblique fractures, no significant difference was found among the four groups in terms of stiffness in the axial compression experiment (P = 0.257). The torsion angle of the LCP + LAP system was significantly higher compared with the OBS system (P < 0.05). When simulating a comminuted fracture, the experimental data for axial compression showed that the rigidity measurements of the three combinations of the OBS system were higher compared with the LCP + LAP system (P = 0.000) and that the torsion angles of three combinations of the OBS system were smaller compared with the LCP + LAP system (P < 0.05). In the axial compression failure test, the fixed failure mode of the LCP + LAP system was the destruction of the contact cortex at the fracture site, whereas the failure modes in the three OBS combinations involved fracture around the screws above the osteotomy and destruction of the contact cortex at the fracture site. CONCLUSIONS The findings revealed that the OBS produced superior biomechanical outcomes compared with LCP + LAP, especially for the bridging two-rod dual cortex. According to the performance observed after model axial compression destruction, the OBS was fixed and provided greater stress dispersion, which might make it more suitable for facilitating early functional movement and avoiding the failure of internal fixation.
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Affiliation(s)
- Yuntao Long
- Shandong First Medical University & Shandong Academy Medical Sciences, Jinan, 250117, Shandong, China
| | - Yubin Qi
- Department of Orthopaedics, The First Affiliated Hospital of Shandong First Medical University & Shandong Provincial Qianfoshan Hospital, Jinan, 250014, Shandong, China
| | - Guilai Zuo
- Department of Orthopaedics, The First Affiliated Hospital of Shandong First Medical University & Shandong Provincial Qianfoshan Hospital, Jinan, 250014, Shandong, China
| | - Qingjie Zhang
- Newton Laboratories, Tianjin Weiman Biomaterials Co., Ltd, Tianjin, 301600, China
| | - Zhenlin Liu
- Newton Laboratories, Tianjin Weiman Biomaterials Co., Ltd, Tianjin, 301600, China
| | - Wen Wang
- Department of Orthopaedics, The First Affiliated Hospital of Shandong First Medical University & Shandong Provincial Qianfoshan Hospital, Jinan, 250014, Shandong, China.
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Abstract
Bone is an outstanding, well-designed composite. It is constituted by a multi-level structure wherein its properties and behavior are dependent on its composition and structural organization at different length scales. The combination of unique mechanical properties with adaptive and self-healing abilities makes bone an innovative model for the future design of synthetic biomimetic composites with improved performance in bone repair and regeneration. However, the relation between structure and properties in bone is very complex. In this review article, we intend to describe the hierarchical organization of bone on progressively greater scales and present the basic concepts that are fundamental to understanding the arrangement-based mechanical properties at each length scale and their influence on bone’s overall structural behavior. The need for a better understanding of bone’s intricate composite structure is also highlighted.
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A New System for Periprosthetic Fracture Stabilization-A Biomechanical Comparison. J Clin Med 2022; 11:jcm11030892. [PMID: 35160342 PMCID: PMC8836720 DOI: 10.3390/jcm11030892] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2021] [Revised: 01/26/2022] [Accepted: 02/05/2022] [Indexed: 11/23/2022] Open
Abstract
In recent years, an increase in periprosthetic femur fractures has become apparent due to the increased number of hip replacements. In the case of Vancouver type B1 fractures, locking plate systems offer safe procedures. This study compared the distal lateral femur plate (LOQTEQ®, aap Implantate AG) with a standard L.I.S.S. LCP® (DePuy Synthes) regarding their biomechanical properties in fixation of periprosthetic femur fractures after hip arthroplasty. We hypothesized that the new LOQTEQ system has superior stability and durability in comparison. Eighteen artificial left femurs were randomized in two groups (Group A: LOQTEQ®; Group B: L.I.S.S. LCP®) and tested until failure. Failure was defined as 10° varus deformity and catastrophic implant failure (loosening, breakage, progressive bending). Axial stiffness, loads of failure, cycles of failure, modes of failure were recorded. The axial stiffness in Group A with 73.4 N/mm (SD +/− 3.0) was significantly higher (p = 0.001) than in Group B (40.7 N/mm (SD +/− 2.8)). Group A resists more cycles than Group B until 10° varus deformity. Catastrophic failure mode was plate breakage in Group A and bending in Group B. In conclusion, LOQTEQ® provides higher primary stability and tends to have higher durability.
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Cho HM, Choi SM, Park JY, Lee Y, Bae JH. A finite element analysis and cyclic load experiment on an additional transcortical-type hole formed around the proximal femoral nail system's distal locking screw. BMC Musculoskelet Disord 2022; 23:92. [PMID: 35086522 PMCID: PMC8793818 DOI: 10.1186/s12891-022-05006-4] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/20/2021] [Accepted: 12/21/2021] [Indexed: 01/21/2023] Open
Abstract
BACKGROUND A complication associated with the distal locking screw used in the proximal femoral nail (PFN) system is the formation of accidental additional holes. We hypothesized that an increase in stress around additional holes is a relevant factor contributing to fractures. This study aimed to evaluate stress changes in the cortical bone around additional screw holes using finite element analysis. METHODS Proximal femoral nail antirotation (PFNA)-II (Synthes, Solothurn, Switzerland) was inserted into a femur model. An additional 4.9-mm transcortical hole was made either anteriorly (anterior hole model) or posteriorly (posterior hole model) to the distal locking screw. Finite element analysis was used to calculate compression, tension, and load limits to investigate stress around additional holes with respect to the direction of screw penetration and degree of osteoporosis. The results were then compared with those of mechanical testing. A 31A-21 type intertrochanteric fracture was applied. As a control group, a model without additional holes (no-hole model) was developed. Repeated load-loading tests were performed on 10 model bones per model group. RESULTS Tensile stress was significantly greater in the no-hole model when additional screw holes were present, and the anterior hole showed a higher maximum stress value than the posterior hole, suggesting that the anterior hole was more susceptible to fracture. The change in tensile stress first appeared in the hole around the lateral cortical bone and proceeded to the medial side. Biomechanical testing showed that fractures around the distal locking screw occurred in 0 cases of the no-hole, 10 of the anterior hole, and 9 of the posterior hole models. CONCLUSIONS During PFN surgery for intertrochanteric fracture, holes with distal locking screws fixed and removed at the anterior and posterior of the nail can be a risk factor for fractures in the surrounding area.
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Affiliation(s)
- Hong Man Cho
- Department of Orthopedic Surgery, Gwangju Veterans Hospital, 99 Cheomdanwolbong-ro, Gwangsan-gu, Gwangju, 62284, South Korea.
| | - Seung Min Choi
- Department of Orthopedic Surgery, Inchon Veterans Hospital, Inchon, South Korea
| | - Ji Yeon Park
- Department of Orthopedic Surgery, Gwangju Veterans Hospital, 99 Cheomdanwolbong-ro, Gwangsan-gu, Gwangju, 62284, South Korea
| | - Young Lee
- Veterans Medical Research Institute, Veterans Health Service Medical Center, Seoul, South Korea
| | - Jung Hyung Bae
- ENS Corp, Bio-medical Material and Component Service Center, Gwangju, South Korea
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Zhan S, Jiang D, Ling M, Ding J, Yang K, Duan L, Tsai TY, Feng Y, van Trigt B, Jia W, Zhang C, Hu H. Fixation effects of different types of cannulated screws on vertical femoral neck fracture: A finite element analysis and experimental study. Med Eng Phys 2021; 97:32-39. [PMID: 34756336 DOI: 10.1016/j.medengphy.2021.09.007] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2020] [Revised: 09/23/2021] [Accepted: 09/24/2021] [Indexed: 12/21/2022]
Abstract
Femoral neck fractures (FNFs) in young patients usually result from high-energy violence, and the vertical transcervical type is typically challenging for its instability. FNFs are commonly treated with three cannulated screws (CS), but the role of screws type on fixation effects (FE) is unclear. The purpose of this study was to evaluate the FE of ten types of CS with different diameters, lengths, depths, and pitches of thread via finite element analysis which was validated by a biomechanical test. Ten vertical FNF models were grouped, fixed by ten types of CS, respectively, all in a parallel, inverted triangular configuration. Their FE were scored comprehensively from six aspects via an entropy evaluation method, as higher scores showed better results. For partial-thread screws, thread length and thread shape factor (TSF) are determinative factors on stability of FNF only if thread depth is not too thick, and they have less cut-out risk, better compression effects and better detached resistance of fracture than full-thread screws, whereas full-thread screws appear to have better shear and shortening resistance. A combination of two superior partial-thread screws and one inferior full-thread screw for vertical FNF may get optimal biomechanical outcomes. The type of cannulated screw is important to consider when treating vertical FNF.
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Affiliation(s)
- Shi Zhan
- Biomechanical Laboratory of Orthopedic Surgery Department, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai, 200233, PR China
| | - Dajun Jiang
- Biomechanical Laboratory of Orthopedic Surgery Department, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai, 200233, PR China
| | - Ming Ling
- Biomechanical Laboratory of Orthopedic Surgery Department, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai, 200233, PR China
| | - Jian Ding
- Department of Orthopedic Surgery, Shanghai Jiaotong University Affiliated Sixth People's Hospital, Shanghai, 200233, PR China
| | - Kai Yang
- Radiology Department, Shanghai Jiaotong University Affiliated Sixth People's Hospital, Shanghai, 200233, PR China
| | - Lei Duan
- State Key Laboratory of Ocean Engineering, School of Naval Architecture, Ocean & Civil Engineering, Shanghai Jiao Tong University, Shanghai, 200240, PR China
| | - Tsung-Yuan Tsai
- Engineering Research Center of Clinical Translational Digital Medicine, Ministry of Education of P.R. China, School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai, 200030, PR China
| | - Yong Feng
- Biomechanical Laboratory of Orthopedic Surgery Department, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai, 200233, PR China
| | - Bart van Trigt
- Department of Biomechanical Engineering, Delft University of Technology, Mekelweg 4, 2628 CD Delft, the Netherlands
| | - Weitao Jia
- Department of Orthopedic Surgery, Shanghai Jiaotong University Affiliated Sixth People's Hospital, Shanghai, 200233, PR China.
| | - Changqing Zhang
- Biomechanical Laboratory of Orthopedic Surgery Department, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai, 200233, PR China.
| | - Hai Hu
- Biomechanical Laboratory of Orthopedic Surgery Department, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai, 200233, PR China.
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Xia Y, Zhang W, Hu H, Yan L, Zhan S, Wang J. Biomechanical study of two alternative methods for the treatment of vertical femoral neck fractures - A finite element analysis. COMPUTER METHODS AND PROGRAMS IN BIOMEDICINE 2021; 211:106409. [PMID: 34560605 DOI: 10.1016/j.cmpb.2021.106409] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/07/2021] [Accepted: 09/06/2021] [Indexed: 06/13/2023]
Abstract
BACKGROUND No consensus has been reached for the treatment of vertical femoral neck fractures (vFNFs). Recently, two alternative methods were invented to treat vFNFs, one of which is a new plate with a sliding groove, which was designed as a substitution of the medial buttress locking plate to combine with cannulated compression screws (CCS) for reducing the breakage possibility of the proximal locking screw during the bone healing. Another one is the femoral neck system (FNS), which was believed with biomechanical superiority. This study aims to compare the biomechanics of these two new implants with three previous methods via finite element analysis (FEA) to validate whether they are suitable for the treatment of vFNFs. METHODS Five 70-degree Pauwels type III transcervical FNFs (vFNFs, AO/OTA 31B2.3r) models were built and fixed by CCS augmented with the newly designed sliding groove buttress plate (CCS+BS) and FNS. For comparison, models fixed by three parallel cannulated compression screws (CCS), biplane double-supported screw fixation (BDSF), CCS augmented with a medial buttress locking plate (CCS+BL) were also built. A 2100N load was applied along with the mechanical axis. Parameters of the maximal stress as well as the maximal displacement of the implants and bone, the maximal relative displacement of interfragments, and the stiffness, were analyzed to compare the biomechanical characteristics of the five models. RESULTS CCS+BS and CCS+BL showed stronger fixation strength with improved stiffness (1012.05N/mm, 1092.04N/mm), reduced maximal displacement of the implants (1.976mm, 1.838mm) and bone (2.075mm, 1.923mm), when compared with CCS (925.11N/mm, 2.158mm and 2.270mm) and BDSF (842.36N/mm, 2.299mm and 2.493mm). While FNS showed the weakest stiffness (593.22N/mm) and largest maximal displacement of the implants (3.234mm) and bone (3.540mm) among the five models. CONCLUSIONS CCS+BS has a better biomechanical performance than CCS and BDSF, which offers a new choice to deal with vFNFs. The construction stability of FNS is weaker than CCS, BDSF, and CCS+BL, indicating that this method may not as stable as reported in the previous study.
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Affiliation(s)
- Yutong Xia
- Dalian Medical University, Dalian 116044, Liaoning Province, China
| | - Wendong Zhang
- Department of Orthopedics, Subei People's Hospital of Jiangsu Province, Yangzhou 225001, Jiangsu Province, China
| | - Hai Hu
- Orthopedic Biomechanical Laboratory of Department of Orthopedic Surgery, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai 200233, China
| | - Lianqi Yan
- Department of Orthopedics, Subei People's Hospital of Jiangsu Province, Yangzhou 225001, Jiangsu Province, China.
| | - Shi Zhan
- Orthopedic Biomechanical Laboratory of Department of Orthopedic Surgery, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai 200233, China.
| | - Jingcheng Wang
- Dalian Medical University, Dalian 116044, Liaoning Province, China; Department of Orthopedics, Subei People's Hospital of Jiangsu Province, Yangzhou 225001, Jiangsu Province, China.
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Mu JX, Xiang SY, Ma QY, Gu HL. Selection of internal fixation method for femoral intertrochanteric fractures using a finite element method. World J Clin Cases 2021; 9:6343-6356. [PMID: 34435000 PMCID: PMC8362576 DOI: 10.12998/wjcc.v9.i22.6343] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/07/2021] [Revised: 05/23/2021] [Accepted: 06/03/2021] [Indexed: 02/06/2023] Open
Abstract
BACKGROUND Failure to fix unstable intertrochanteric fractures impairs return to daily activities.
AIM To simulate five different internal fixation methods for unstable proximal femoral fractures.
METHODS A three-dimensional model of the femur was established from sectional computed tomography images, and an internal fixation model was established. Finite element analysis of the femur model was established, and three intertrochanteric fracture models, medial defect, lateral defect, and medial-lateral defects, were simulated. Displacement and stress distribution after fixation with a proximal femoral anti-rotation intramedullary nail (PFNA), integrated dual-screw fixation (ITN), PFNA + wire, PFNA + plate, and PFNA + wire + plate were compared during daily activities.
RESULTS The maximum displacement and stress of PFNA and ITN were 3.51 mm/473 MPa and 2.80 mm/588 MPa for medial defects; 2.55 mm/288 MPa and 2.10 mm/307 MPa for lateral defects; and 3.84 mm/653 MPa and 3.44 mm/641 MPa for medial-lateral defects, respectively. For medial-lateral defects, reconstructing the medial side alone changed the maximum displacement and stress to 2.79 mm/515 MPa; reconstructing the lateral side changed them to 3.72 mm/608 MPa, when both sides were reconstructed, they changed to 2.42 mm/309 MPa.
CONCLUSION For medial defects, intramedullary fixation would allow early low-intensity rehabilitation exercise, and ITN rather than PFNA reduces the risk of varus and cut-out; for lateral wall defects or weakness, intramedullary fixation allows higher-intensity rehabilitation exercise, and ITN reduces the risk of varus. For both medial and lateral defects, intramedullary fixation alone will not allow early functional exercise, but locating lateral or medial reconstruction will. For defects in both the inner and outer sides, if reconstruction cannot be completed, ITN is more stable.
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Affiliation(s)
- Jia-Xuan Mu
- Department of Orthopedics, Shengjing Hospital, China Medical University, Shenyang 117004, Liaoning Province, China
| | - Shi-Yang Xiang
- Department of Orthopedics, Shengjing Hospital, China Medical University, Shenyang 117004, Liaoning Province, China
| | - Qing-Yu Ma
- Department of Orthopedics, Shengjing Hospital, China Medical University, Shenyang 117004, Liaoning Province, China
| | - Hai-Lun Gu
- Department of Orthopedics, Shengjing Hospital, China Medical University, Shenyang 117004, Liaoning Province, China
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Sarwar A, Gee A, Bougherara H, Kuzyk PRT, Schemitsch EH, Zdero R. Biomechanical optimization of the far cortical locking technique for early healing of distal femur fractures. Med Eng Phys 2021; 89:63-72. [PMID: 33608126 DOI: 10.1016/j.medengphy.2021.02.003] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2020] [Revised: 01/22/2021] [Accepted: 02/03/2021] [Indexed: 10/22/2022]
Abstract
This finite element study optimized far cortical locking (FCL) technology for early callus formation in distal femur fracture fixation with a 9-hole plate using FCL screws proximal to, and standard locking screws distal to, the fracture. Analyses were done for 120 possible FCL screw configurations by varying FCL screw distribution and number. A hip joint force of 700 N (i.e. 100% x body weight) was used, which corresponds to a typical 140 N "toe-touch" foot-to-ground force (i.e. 20% x body weight) suggested to patients immediately after surgery. Increased FCL screw distribution (i.e. shorter plate working length) caused a decrease at the medial side and an increase at the lateral side of the axial interfragmentary motion (AIM), mildly affected shaft and condylar cortex Von Mises max stress (σMAX), increased plate σMAX, and decreased shaft FCL screw and condylar locking screw σMAX. Increased FCL screw number decreased AIM and σMAX on the shaft cortex, condylar cortex, plate, and FCL screws, but not condylar screws. The optimal FCL screw configuration had 3 FCL screws in plate holes #1, 5, and 6 (proximal to distal) for optimal AIM of 0.2 - 1 mm and reduce shear fracture motion, thereby encouraging early callus formation.
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Affiliation(s)
- Ahmed Sarwar
- Department of Mechanical and Industrial Engineering, Ryerson University, Toronto, ON, Canada
| | - Aaron Gee
- Orthopaedic Biomechanics Lab, Victoria Hospital, (Room A6-144), 800 Commissioners Road, London, ON N6A-5W9, Canada
| | - Habiba Bougherara
- Department of Mechanical and Industrial Engineering, Ryerson University, Toronto, ON, Canada
| | - Paul R T Kuzyk
- Department of Surgery, University of Toronto, Toronto, ON, Canada
| | - Emil H Schemitsch
- Orthopaedic Biomechanics Lab, Victoria Hospital, (Room A6-144), 800 Commissioners Road, London, ON N6A-5W9, Canada; Department of Surgery, Western University, London, ON, Canada
| | - Radovan Zdero
- Department of Mechanical and Industrial Engineering, Ryerson University, Toronto, ON, Canada; Orthopaedic Biomechanics Lab, Victoria Hospital, (Room A6-144), 800 Commissioners Road, London, ON N6A-5W9, Canada; Department of Surgery, Western University, London, ON, Canada; Department of Mechanical and Materials Engineering, Western University, London, ON, Canada.
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Ziebart C, PT CM, PT JL. Low Risk of Fracture With End-Range Movements of the Hip in People With Low Bone Mineral Density: A Narrative Review. Gerontol Geriatr Med 2021; 7:23337214211052398. [PMID: 34820484 PMCID: PMC8606974 DOI: 10.1177/23337214211052398] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2021] [Revised: 09/22/2021] [Accepted: 09/23/2021] [Indexed: 11/16/2022] Open
Abstract
Background: The risks of end-range movements for people with osteoporosis, specifically at the hips and shoulder, are not well understood. Objectives: To synthesize literature on the safety of stretching for people with osteoporosis by searching: 1) biomechanical literature to determine how much force results from an end-range maneuverer and is required to fracture joint components (focusing on the hip joint) and 2) clinical literature to describe techniques used, populations studied, effects, and reported adverse events. Methods: We conducted two separate search strategies in PubMed, EMBASE, and Scopus (1955-2020). Results: 16 articles described either biomechanical or clinical effects of passive and active end ranges of the hip joint. The largest load in the hip, described in the literature was in a crescent lunge during yoga. The moment produced in a crescent lunge is much smaller than that of the tensile strength of osteoporotic bone, suggesting the crescent lunge movement could be considered safe. Clinically, no adverse events were reported in exercise, stretching or yoga interventions. Conclusion: This review found no evidence that end range movements of the hip are unsafe, but there is little evidence. No studies were identified that explored the risk of humeral fracture during end range stretches.
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Affiliation(s)
- Christina Ziebart
- Health and Rehabilitation Sciences, Western University, 1201 Western Rd., London, ON N6A 3K7, Canada
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Zhan S, Jiang D, Xu J, Ling M, Yang K, Li Y, Jia W, Hu H, Zhang C. Influence of the proximal screws of buttress plates on the stability of vertical femoral neck fractures: a finite element analysis. BMC Musculoskelet Disord 2020; 21:842. [PMID: 33308185 PMCID: PMC7733615 DOI: 10.1186/s12891-020-03853-7] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/08/2020] [Accepted: 12/01/2020] [Indexed: 11/18/2022] Open
Abstract
Background The treatment of vertical femoral neck fractures (vFNFs) in young patients remains challenging, with a high complication rate by using traditional techniques. The use of cannulated screws (CSs) combined with a buttress plate represents an alternative approach for treating vFNFs. However, the biomechanical influence of the use or non-use of the proximal screws of buttress plates on vFNFs stability remains unclear. This study aims to analyse the biomechanics of buttress plate fixation with or without the use of proximal screws through finite element analysis (FEA) to further understand this approach. Methods We built five vFNFs (Pauwels angle 70°) finite element models treated using three cannulated screws (CS group) or three cannulated screws plus a locking buttress plate (buttress group). In the buttress group, use or non-use of proximal screws was carried out on two types of plates (4-hole & 6-hole). The following seven parameters were analysed to compare biomechanical properties of the five models: the stiffness; the maximal stress of the plate system (plate and screws), CSs and bone (MPS, MCS, MBS); the maximal displacement of internal fixations (plate system & CSs) and bone (MIFD, MBD); and the maximal relative displacement of interfragments (MID). Results Compared with CS model, the buttress models exhibited improved biomechanical properties, with increased stiffness and decreased MCS, MBS, MIFD, MBD and MID. The models fixed using buttress plates combined with a proximal screw showed greater stiffness (+ 3.75% & + 8.31% vs + 0.98% & + 4.57%) and MPS (795.6 & 947.2 MPa vs 294.9 & 556.2 MPa) values, and smaller MCS, MBS, MIFD, MBD and MID (− 3.41% to − 15.35% vs − 0.07% to − 4.32%) values than those using the same length plates without a proximal screw. Conclusions Based on the FEA results, buttress plates can improve construct mechanics, help to resist shear force and prevent varus collapse; under the modelling conditions, the use of a proximal screw on buttress plate may be a key technical feature in improving anti-shearing ability; additionally, this screw may be essential to reduce stress and prevent re-displacement of cannulated screws and fracture fragments.
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Affiliation(s)
- Shi Zhan
- Orthopedic Biomechanical Laboratory of Department of Orthopedic Surgery, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, NO. 600, Yishan Rd., Shanghai, 200233, People's Republic of China
| | - Dajun Jiang
- Orthopedic Biomechanical Laboratory of Department of Orthopedic Surgery, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, NO. 600, Yishan Rd., Shanghai, 200233, People's Republic of China
| | - Jian Xu
- Orthopedic Biomechanical Laboratory of Department of Orthopedic Surgery, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, NO. 600, Yishan Rd., Shanghai, 200233, People's Republic of China
| | - Ming Ling
- Department of Orthopedic, Fudan University Affiliated Huadong Hospital, Shanghai, 200040, People's Republic of China
| | - Kai Yang
- Radiology Department, Shanghai Jiaotong University Affiliated Sixth People's Hospital, Shanghai, 200233, People's Republic of China
| | - Yuehua Li
- Radiology Department, Shanghai Jiaotong University Affiliated Sixth People's Hospital, Shanghai, 200233, People's Republic of China
| | - Weitao Jia
- Department of Orthopedic Surgery, Shanghai Jiaotong University Affiliated Sixth People's Hospital, Shanghai, 200233, People's Republic of China.
| | - Hai Hu
- Orthopedic Biomechanical Laboratory of Department of Orthopedic Surgery, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, NO. 600, Yishan Rd., Shanghai, 200233, People's Republic of China. .,Department of Orthopedic Surgery, Shanghai Jiaotong University Affiliated Sixth People's Hospital, Shanghai, 200233, People's Republic of China.
| | - Changqing Zhang
- Orthopedic Biomechanical Laboratory of Department of Orthopedic Surgery, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, NO. 600, Yishan Rd., Shanghai, 200233, People's Republic of China. .,Department of Orthopedic Surgery, Shanghai Jiaotong University Affiliated Sixth People's Hospital, Shanghai, 200233, People's Republic of China.
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Li JJ, Tian DM, Yang L, Zhang JY, Hu YC. Influence of a metaphyseal sleeve on the stress-strain state of a bone-tumor implant system in the distal femur: an experimental and finite element analysis. J Orthop Surg Res 2020; 15:589. [PMID: 33298115 PMCID: PMC7724731 DOI: 10.1186/s13018-020-02025-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/24/2020] [Accepted: 10/14/2020] [Indexed: 12/03/2022] Open
Abstract
Background Aseptic loosening of distal femoral tumor implants significantly correlates with the resection length. We designed a new “sleeve” that is specially engaged in the metaphysis at least 5 cm proximal to the knee joint line to preserve as much bone stock as possible. This study investigates the influence of a metaphyseal sleeve on the stress-strain state of a bone tumor implant system in the distal femur. Methods Cortex strains in intact and implanted femurs were predicted with finite element (FE) models. Moreover strains were experimentally measured in a cadaveric femur with and without a sleeve and stem under an axial compressive load of 1000 N. The FE models, which were validated by linear regression, were used to investigate the maximal von Mises stress and the implanted-to-intact (ITI) ratios of strain in the femur with single-legged stance loading under immediate postoperative and osseointegration conditions. Results Good agreement was noted between the experimental measurements and numerical predictions of the femoral strains (coefficient of determination (R2) ≥ 0.95; root-mean-square error (RMSE%) ≈ 10%). The ITI ratios for the metaphysis were between 13 and 28% and between 10 and 21% under the immediate postoperative and osseointegration conditions, respectively, while the ITI ratios for the posterior and lateral cortices around the tip of the stem were 110% and 119% under the immediate-postoperative condition, respectively, and 114% and 101% under the osseointegration condition, respectively. The maximal von Mises stresses for the implanted femur were 113.8 MPa and 43.41 MPa under the immediate postoperative and osseointegration conditions, which were 284% and 47% higher than those in the intact femur (29.6 MPa), respectively. Conclusions This study reveals that a metaphyseal sleeve may cause stress shielding relative to the intact femur, especially in the distal metaphysis. Stress concentrations might mainly occur in the posterior cortex around the tip of the stem. However, stress concentrations may not be accompanied by periprosthetic fracture under the single-legged stance condition.
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Affiliation(s)
- Jian-Jun Li
- Tianjin Medical University, 22 Qixiangtai Road, Tianjin, People's Republic of China.,Department of Bone Oncology, Tianjin Hospital, 406 Jiefang Southern Road, Tianjin, People's Republic of China.,Department of Bone Trauma, Second Hospital of Tangshan, 22 Jianshe North Road, Tangshan, Hebei, People's Republic of China
| | - Dong-Mu Tian
- Beijing Weigao Yahua Artificial Joint Development Company, 7 Niuhui Street, Shunyi, Beijing, People's Republic of China
| | - Li Yang
- Tianjin Medical University, 22 Qixiangtai Road, Tianjin, People's Republic of China
| | - Jing-Yu Zhang
- Department of Bone Oncology, Second Hospital of Tangshan, 22 Jianshe North Road, Tangshan, Hebei, People's Republic of China
| | - Yong-Cheng Hu
- Department of Bone Oncology, Tianjin Hospital, 406 Jiefang Southern Road, Tianjin, People's Republic of China.
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Gee A, Bougherara H, Schemitsch EH, Zdero R. Biomechanical design using in-vitro finite element modeling of distal femur fracture plates made from semi-rigid materials versus traditional metals for post-operative toe-touch weight-bearing. Med Eng Phys 2020; 87:95-103. [PMID: 33461680 DOI: 10.1016/j.medengphy.2020.11.015] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2020] [Revised: 11/23/2020] [Accepted: 11/29/2020] [Indexed: 01/19/2023]
Abstract
This proof-of-concept study designs distal femur fracture plates from semi-rigid materials vs. traditional metals for toe-touch weight-bearing recommended to patients immediately after surgery. The two-fold goal was to (a) reduce stress shielding (SS) by increasing cortical bone stress thereby reducing the risk of bone absorption and plate loosening, and (b) reduce delayed healing (DH) via early callus formation by optimizing axial interfragmentary motion (AIM). Finite element analysis was used to design semi-rigid plates whose elastic moduli E ensured plates permitted AIM of 0.2 - 1 mm for early callus formation. A low hip joint force of 700 N (i.e. 100% x body weight) was applied, which corresponds to a typical 140 N toe-touch foot-to-ground force (i.e. 20% x body weight) recommended to patients after surgery. Analysis was done using 2 screw materials (steel or titanium) and types (locked or non-locked). Steel and titanium plates were also analyzed. Semi-rigid plates (vs. metal plates) had lower overall femur/plate construct stiffnesses of 508 - 1482 N/mm, higher cortical bone stresses under the plate by 2.02x - 3.27x thereby reducing SS, and lower E values of 414 - 2302 MPa to permit AIM of 0.2 - 1 mm thereby reducing DH.
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Affiliation(s)
- Aaron Gee
- Orthopaedic Biomechanics Lab, Room A6-144, Victoria Hospital, 800 Commissioners Road, London N6A5W9, Canada.
| | - Habiba Bougherara
- Department of Mechanical and Industrial Engineering, Ryerson University, Toronto, Canada.
| | - Emil H Schemitsch
- Orthopaedic Biomechanics Lab, Room A6-144, Victoria Hospital, 800 Commissioners Road, London N6A5W9, Canada; Department of Surgery (Division of Orthopaedic Surgery), Western University, London, Canada.
| | - Radovan Zdero
- Orthopaedic Biomechanics Lab, Room A6-144, Victoria Hospital, 800 Commissioners Road, London N6A5W9, Canada; Department of Mechanical and Industrial Engineering, Ryerson University, Toronto, Canada; Department of Surgery (Division of Orthopaedic Surgery), Western University, London, Canada; Department of Mechanical and Materials Engineering, Western University, London, Canada.
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Wisanuyotin T, Sirichativapee W, Paholpak P, Kosuwon W, Kasai Y. Optimal configuration of a dual locking plate for femoral allograft or recycled autograft bone fixation: A finite element and biomechanical analysis. Clin Biomech (Bristol, Avon) 2020; 80:105156. [PMID: 32862075 DOI: 10.1016/j.clinbiomech.2020.105156] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/09/2020] [Revised: 07/23/2020] [Accepted: 08/19/2020] [Indexed: 02/07/2023]
Abstract
BACKGROUND Allografts and recycled bone autograft are commonly used for biological reconstruction. The dual locking plates fixation method has been advocated for increasing allograft stability and preventing fixation failure; however, the biomechanical properties of the various configurations of dual locking plates have not been extensively studied. METHODS In a finite element (FE) analysis, we developed 6 patterns of different dual locking plate configurations for fixation of the mid shaft of the femur. The maximum strains were recorded for each of the 6 models then axial, bending and torsion stiffness were calculated. The FE analysis was validated the results with mechanical testing (axial compression, bending, and torsional stiffness) on a cadaveric femur. FINDINGS The highest axial compression (715.41 N/mm) and lateral bending (2981.24 N/mm) was found in Model 4 (with two 10-hole locking plates placed at the medial and lateral side), while the highest torsional stiffness (193.59 N·mm /mm) was found in Model 3 (with 8- and 10-hole locking plates placed at the posterior and lateral side). Excellent agreement was found between the finite element analysis and biomechanical testing (r2 = 0.98). INTERPRETATION The dual locking plate configuration with medial and lateral, 10-hole locking plates provided the most rigid and strongest fixation of the femur; both in terms of axial compression and lateral bending stiffness.
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Affiliation(s)
- Taweechok Wisanuyotin
- Department of Orthopaedics, Faculty of Medicine, Khon Kaen University, 40002, Thailand.
| | - Winai Sirichativapee
- Department of Orthopaedics, Faculty of Medicine, Khon Kaen University, 40002, Thailand
| | - Permsak Paholpak
- Department of Orthopaedics, Faculty of Medicine, Khon Kaen University, 40002, Thailand
| | - Weerachai Kosuwon
- Department of Orthopaedics, Faculty of Medicine, Khon Kaen University, 40002, Thailand
| | - Yuichi Kasai
- Department of Orthopaedics, Faculty of Medicine, Khon Kaen University, 40002, Thailand
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Application of Fibre Bragg Grating Sensors in Strain Monitoring and Fracture Recovery of Human Femur Bone. Bioengineering (Basel) 2020; 7:bioengineering7030098. [PMID: 32825200 PMCID: PMC7552668 DOI: 10.3390/bioengineering7030098] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2020] [Revised: 08/03/2020] [Accepted: 08/17/2020] [Indexed: 11/17/2022] Open
Abstract
Fibre Bragg Grating (FBG) sensors are gaining popularity in biomedical engineering. However, specific standards for in vivo testing for their use are absolutely limited. In this study, in vitro experimental tests were performed to investigate the behaviors and applications of gratings attached to intact and fractured thighbone for a range of compression loading (<300 N) based around some usual daily activities. The wavelength shifts and the corresponding strain sensitivities of the FBG sensors were measured to determine their effectiveness in monitoring the femoral fracture healing process. Four different arrangements of FBG sensors were selected to measure strains at different critical locations on the femoral sawbones surface. Data obtained for intact and plated sawbones were compared using both embedded longitudinal and coiled FBG arrays. Strains were measured close to the fracture, posterior linea aspera and popliteal surface areas, as well as at the proximal and distal ends of the synthetic femur; their responses are discussed herein. The gratings on the longitudinally secured FBG arrays were found to provide high levels of sensitivity and precise measurements, even for relatively small loads (<100 N). Nevertheless, embedding angled FBG sensors is essential to measure the strain generated by applied torque on the femur bone. The maximum recorded strain of the plated femur was 503.97 µε for longitudinal and -274.97 µε for coiled FBG arrays, respectively. These project results are important to configure effective arrangements and orientations of FBG sensors with respect to fracture position and fixation implant for future in vivo experiments.
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Tatani I, Megas P, Panagopoulos A, Diamantakos I, Nanopoulos P, Pantelakis S. Comparative analysis of the biomechanical behavior of two different design metaphyseal-fitting short stems using digital image correlation. Biomed Eng Online 2020; 19:65. [PMID: 32814586 PMCID: PMC7437017 DOI: 10.1186/s12938-020-00806-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2020] [Accepted: 08/04/2020] [Indexed: 01/26/2023] Open
Abstract
BACKGROUND The progressive evolution in hip replacement research is directed to follow the principles of bone and soft tissue sparing surgery. Regarding hip implants, a renewed interest has been raised towards short uncemented femoral implants. A heterogeneous group of short stems have been designed with the aim to approximate initial, post-implantation bone strain to the preoperative levels in order to minimize the effects of stress shielding. This study aims to investigate the biomechanical properties of two distinctly designed femoral implants, the TRI-LOCK Bone Preservation Stem, a shortened conventional stem and the Minima S Femoral Stem, an even shorter and anatomically shaped stem, based on experiments and numerical simulations. Furthermore, finite element models of implant-bone constructs should be evaluated for their validity against mechanical tests wherever it is possible. In this work, the validation was performed via a direct comparison of the FE calculated strain fields with their experimental equivalents obtained using the digital image correlation technique. RESULTS Design differences between Trilock BPS and Minima S femoral stems conditioned different strain pattern distributions. A distally shifting load distribution pattern as a result of implant insertion and also an obvious decrease of strain in the medial proximal aspect of the femur was noted for both stems. Strain changes induced after the implantation of the Trilock BPS stem at the lateral surface were greater compared to the non-implanted femur response, as opposed to those exhibited by the Minima S stem. Linear correlation analyses revealed a reasonable agreement between the numerical and experimental data in the majority of cases. CONCLUSION The study findings support the use of DIC technique as a preclinical evaluation tool of the biomechanical behavior induced by different implants and also identify its potential for experimental FE model validation. Furthermore, a proximal stress-shielding effect was noted after the implantation of both short-stem designs. Design-specific variations in short stems were sufficient to produce dissimilar biomechanical behaviors, although their clinical implication must be investigated through comparative clinical studies.
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Affiliation(s)
- I Tatani
- Orthopaedic Department, University Hospital of Patras, Papanikolaou 1, Rio-Patra, 26504, Patras, Greece.
| | - P Megas
- Orthopaedic Department, University Hospital of Patras, Papanikolaou 1, Rio-Patra, 26504, Patras, Greece
| | - A Panagopoulos
- Orthopaedic Department, University Hospital of Patras, Papanikolaou 1, Rio-Patra, 26504, Patras, Greece
| | - I Diamantakos
- Laboratory of Technology and Strength of Materials, Department of Mechanical Engineering and Aeronautics, University of Patras, Patras, Greece
| | - Ph Nanopoulos
- Department of Computer Engineering & Informatics, University of Patras, Patras, Greece
| | - Sp Pantelakis
- Laboratory of Technology and Strength of Materials, Department of Mechanical Engineering and Aeronautics, University of Patras, Patras, Greece
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Terzini M, Aldieri A, Nurisso S, De Nisco G, Bignardi C. Finite Element Modeling Application in Forensic Practice: A Periprosthetic Femoral Fracture Case Study. Front Bioeng Biotechnol 2020; 8:619. [PMID: 32656199 PMCID: PMC7324477 DOI: 10.3389/fbioe.2020.00619] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2020] [Accepted: 05/20/2020] [Indexed: 11/13/2022] Open
Abstract
The incidence of periprosthetic fractures has rapidly increased in the last two decades and has been the cause of a large number of revision surgeries and permanent physical disability for many patients, as well as a significant socioeconomic burden for many nations. This research deals with a periprosthetic femur fracture real event, occurred following a total hip arthroplasty and treated with one of the most widespread internal fixation methods: the implant of a periprosthetic femur plate system. A Finite Element analysis was performed to investigate the implanted femur plate break after a short follow-up and to understand the plate break causes. Such events are currently object of forensic debate as more and more often hospitals, surgeons, and medical device manufacturers are denounced by patients to whom similar events occur. In this work, different load situations acting on the femur during daily and incidental activities were simulated, in order to validate the correct behavior of the plate, according to the intended use recommended by the manufacturer. The analysis demonstrates that the plate failure can occur in situations of unconventional loading such as that caused by stumbling and in presence of incomplete bone healing.
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Affiliation(s)
- Mara Terzini
- Department of Mechanical and Aerospace Engineering, Politecnico di Torino, Turin, Italy.,PolitoBIOMed Lab, Politecnico di Torino, Turin, Italy
| | - Alessandra Aldieri
- Department of Mechanical and Aerospace Engineering, Politecnico di Torino, Turin, Italy.,PolitoBIOMed Lab, Politecnico di Torino, Turin, Italy
| | - Stefania Nurisso
- Department of Mechanical and Aerospace Engineering, Politecnico di Torino, Turin, Italy.,PolitoBIOMed Lab, Politecnico di Torino, Turin, Italy
| | - Giuseppe De Nisco
- Department of Mechanical and Aerospace Engineering, Politecnico di Torino, Turin, Italy.,PolitoBIOMed Lab, Politecnico di Torino, Turin, Italy
| | - Cristina Bignardi
- Department of Mechanical and Aerospace Engineering, Politecnico di Torino, Turin, Italy.,PolitoBIOMed Lab, Politecnico di Torino, Turin, Italy
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Brazda IJ, Reeves J, Langohr GDG, Crookshank MC, Schemitsch EH, Zdero R. Biomechanical properties and thermal characteristics of frozen versus thawed whole bone. Proc Inst Mech Eng H 2020; 234:874-883. [PMID: 32515277 DOI: 10.1177/0954411920929455] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Biomechanics research often requires cadaveric whole bones to be stored in a freezer and then thawed prior to use; however, the literature shows a variety of practices for thawing. Consequently, this is the first study to report the mechanical properties of fully frozen versus fully thawed whole bone as 'proof of principle'. Two groups of 10 porcine ribs each were statistically equivalent at baseline in length, cross-sectional area, and bone mineral density. The two groups were stored in a freezer for at least 24 h, thawed in air at 23 °C for 4 h while temperature readings were taken to establish the time needed for thawing, and once again returned to the freezer for at least 24 h. Mechanical tests to failure using three-point bending were then done on the 'frozen' group immediately after removal from the freezer and the 'thawed' group when steady-state ambient air temperature was reached. Temperature readings over the entire thawing period were described by the line-of-best-fit formula T = (28.34t - 6.69)/(t + 0.38), where T = temperature in degree Celsius and t = time in hours, such that frozen specimens at t = 0 h had a temperature of -17 °C and thawed specimens at t = 1.75 h reached a steady-state temperature of 20 °C-23 °C. Mechanical tests showed that frozen versus thawed specimens had an average of 32% higher stiffness k, 34% higher ultimate force Fu, 28% lower ultimate displacement δu, 40% lower ultimate work Wu, 43% higher elastic modulus E, 37% higher ultimate normal stress σu, and 33% higher ultimate shear stress τu. Whole ribs failed at midspan primarily by transverse cracking (16 of 20 cases), oblique cracking (three of 20 cases), or surface denting (one of 20 cases), each having unique shapes for force versus displacement graphs differentiated mainly by ultimate force location.
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Affiliation(s)
- Ignace J Brazda
- Orthopaedic Biomechanics Lab, Victoria Hospital, London, ON, Canada
| | - Jacob Reeves
- Department of Mechanical and Materials Engineering, Western University, London, ON, Canada
| | - G Daniel G Langohr
- Department of Mechanical and Materials Engineering, Western University, London, ON, Canada
| | | | - Emil H Schemitsch
- Orthopaedic Biomechanics Lab, Victoria Hospital, London, ON, Canada.,Division of Orthopaedic Surgery, Western University, London, ON, Canada
| | - Radovan Zdero
- Orthopaedic Biomechanics Lab, Victoria Hospital, London, ON, Canada.,Department of Mechanical and Materials Engineering, Western University, London, ON, Canada.,Division of Orthopaedic Surgery, Western University, London, ON, Canada.,Department of Mechanical and Industrial Engineering, Ryerson University, Toronto, ON, Canada
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Crump EK, Quacinella M, Deafenbaugh BK. Does Screw Location Affect the Risk of Subtrochanteric Femur Fracture After Femoral Neck Fixation? A Biomechanical Study. Clin Orthop Relat Res 2020; 478:770-776. [PMID: 32229749 PMCID: PMC7282603 DOI: 10.1097/corr.0000000000000945] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/26/2019] [Accepted: 08/07/2019] [Indexed: 01/31/2023]
Abstract
BACKGROUND Case reports suggest that there is an increased risk of subtrochanteric femur fracture after femoral neck fixation with cannulated screws when the distal-most screw is placed distal to the lesser trochanter. However, to our knowledge, there are no biomechanical data supporting this observation. QUESTIONS/PURPOSES (1) Is there an increased risk of subtrochanteric femur fracture after femoral neck fixation with cannulated screws in normal density and osteoporotic Sawbones when the distal-most screw is started distal to the lesser trochanter? (2) Does the screw starting point position after femoral neck fixation with cannulated screws affect load to failure when normal density and osteoporotic Sawbones are loaded through their mechanical axis? METHODS Normal density and osteoporotic Sawbones femora were instrumented with three cannulated screws in a triangular apex distal configuration with the distal-most screw starting either proximal to, at, or distal to the level of the lesser trochanter. Specimens were loaded along the mechanical axis to failure. The fracture location and ultimate load to failure were compared between groups. RESULTS The screw start point distal to the lesser trochanter resulted in a greater proportion of subtrochanteric femur fractures compared with screw start points at or proximal to the lesser trochanter in the subset of osteoporotic specimens (three of 10 specimens versus 0 of 20 specimens; p = 0.030). No subtrochanteric femur fractures were observed in the normal density specimens. Load to failure was lower when the distal-most screw was started distal to the lesser trochanter than when it was started at or proximal to the lesser trochanter (normal density subset 13,502 ± 1980 N versus 14,675 ±1528 N; osteoporotic subset 8946 ± 1509 N versus 10,026 ± 1256 N; linear regression coefficient 1127 N [95% CI 298 to 1956 N]; adjusted r = 0.71; p = 0.009). CONCLUSIONS A screw start point distal to the lesser trochanter was associated with subtrochanteric femur fractures in the osteoporotic subset. Additionally, there was decreased load to failure when the distal-most screw was started distal to the lesser trochanter. CLINICAL RELEVANCE These data suggest that avoiding a screw start point distal to the level of the lesser trochanter in femoral neck fracture fixation may decrease the risk of catastrophic subtrochanteric femur fractures, especially in patients with osteoporosis. However, it should be noted that a more overall varus screw alignment could theoretically compromise the ability to achieve compression across the fracture, with attendant implications with regard to fracture union in the acute setting.
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Affiliation(s)
- Erica K Crump
- E. K. Crump, M. Quacinella, B. K. Deafenbaugh, Department of Orthopaedics, Naval Medical Center San Diego, San Diego, CA, USA
| | - Michael Quacinella
- E. K. Crump, M. Quacinella, B. K. Deafenbaugh, Department of Orthopaedics, Naval Medical Center San Diego, San Diego, CA, USA
| | - Bradley K Deafenbaugh
- E. K. Crump, M. Quacinella, B. K. Deafenbaugh, Department of Orthopaedics, Naval Medical Center San Diego, San Diego, CA, USA
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