• calcium phosphate cement
• cement-augmented pedicle screws
• minimally invasive spine stabilization
• osteoporotic vertebral fracture
• vertebroplasty

• Allograft
• Bone graft substitutes
• Demineralized bone matrix
• Spine fusion
• rh-BMP

• ICOS-Fc
• PLGA nanoparticles
• bone
• calcium sulphate
• injectable cement
• mesoporous bioactive glasses
• osteoporosis
• tissue regeneration

• Humans
• Fractures, Compression/drug therapy
• Spinal Fractures/drug therapy
• Calcium Sulfate
• Bone Cements/pharmacology
• Bone Cements/therapeutic use
• Bone Resorption
• Inducible T-Cell Co-Stimulator Protein

• adolescents
• calcium phosphate cement
• kyphoplasty
• posttraumatic intervertebral disk degeneration

• Fractures
• Minimally invasive surgery
• Tibial plateau
• Tibioplasty

• Humans
• Fracture Fixation, Internal/methods
• Fractures, Compression
• Depression
• Spinal Fractures
• Tibial Fractures/diagnostic imaging
• Tibial Fractures/surgery
• Treatment Outcome

To evaluate the effect of cement augmentation of cortical bone trajectory (CBT) screws using a novel calcium phosphate–based nanocomposite (CPN).

CBT screws were placed into cadaveric lumbar vertebrae. Depending on the material used for augmentation, they were divided into the following three groups: CPN, polymethylmethacrylate (PMMA), and control. Radiological imaging was used to evaluate the cement dispersion. Biomechanical tests were conducted to measure the stability of CBT screws. A rat cranial defect model was used to evaluate biodegradation and osseointegration of the CPN.

After cement augmentation, the CPN tended to disperse into the distal part of the screws, whereas PMMA remained limited to the proximal part of the screws (P < 0.05). As for cement morphology, the CPN tended to form a concentrated mass, whereas PMMA arranged itself as a scattered cement cloud, but the difference was not significant (P > 0.05). The axial pullout test showed that the average maximal pullout force (Fmax) of CPN-augmented CBT screws was similar to that of the PMMA group (CPN, 1639.56 ± 358.21 N vs PMMA, 1778.45 ± 399.83 N; P = 0.745) and was significantly greater than that of the control group (1019.01 ± 371.98 N; P < 0.05). The average torque value in the CPN group was higher than that in the control group (CPN, 1.51 ± 0.78 N∙m vs control, 0.97 ± 0.58 N∙m) and lower than that in the PMMA group (1.93 ± 0.81 N∙m), but there were no statistically significant differences (P > 0.05). The CPN could be biodegraded and gradually replaced by newly formed bone tissue after 12 weeks in a rat cranial defect model.

The biocompatible CPN could be a valuable augmentation material to enhance CBT screw stability.

• CBT screws
• CPN
• PMMA
• cement augmentation
• osteoporotic spine

Background: The most common type of fracture of the lateral tibial plateau is the Schatzker type II split-depressed fracture. Minimally invasive surgery using balloon reduction appears to be very promising compared to the gold standard using a bone tamp. This surgery aims to have the best reduction and stabilization to benefit from an early passive and active rehabilitation to avoid stiffening and muscle wasting. Using a balloon for fracture reduction has allowed the use of semi-liquid Injectable Bone Cement (IBC) fillers. These fillers can be phosphocalcic or polymethyl methacrylate (PMMA). The latest recommendations on these IBCs in spinal surgery increasingly rule out phosphocalcic fillers because of their low mechanical strength.

Questions/purposes: 1) What is the mechanical influence of IBC filling (PMMA) regarding the split and depression components of a Schatzker type II fracture? 2) What is the mechanical influence of osteosynthesis regarding the split and depression components of a Schatzker type II fracture with or without PMMA filing in three different kinds of percutaneous fixations?

Methods: This biomechanical study was performed on 36 fresh frozen tibia/fibula specimens. Six groups were formed according to the type of percutaneous osteosynthesis or possible PMMA filling. Mechanical strength tests were carried out using a Unicompartmental Knee prosthesis and displacement components were measured on either side of the separation on the anterolateral facet by optical method.

Results: We found a significant difference between cementless and cemented osteosynthesis for depression fracture stabilization (difference −507.56N with 95% confidence interval [−904.17; −110.94] (p-value = 0.026)). The differences between the different types of osteosynthesis were not significant (p-value = 0.58). There was a significant difference between osteosynthesis without cement and osteosynthesis with cement on separation (difference −477.72N [−878.52; −76.93] (p-value = 0.03)). The differences between the different types of fixations were not significant regarding separation (p-value = 0.99).

Conclusion: PMMA cement significantly improves primary stability, regardless of the type of osteosynthesis for a Schatzker type II plateau fracture. Filling with PMMA cement during tuberoplasty seems to be a very promising strategy in association with percutaneous osteosynthesis to allow rapid recovery after surgery.

• child
• eosinophilic granuloma
• kyphoplasty
• pathological vertebral body fracture
• vertebral remodeling

Osteoporotic vertebral fractures often necessitate fusion surgery, with high rates of implant failure. We present a novel bioactive composite of calcium phosphate cement (CPC) and the collagen I mimetic P-15 for pedicle screw augmentation in osteoporotic bone. Methods involved expression analysis of osteogenesis-related genes during osteoblastic differentiation by RT-PCR and immunostaining of osteopontin and Ca²⁺ deposits. Untreated and decalcified sheep vertebrae were utilized for linear pullout testing of pedicle screws. Bone mineral density (BMD) was measured using dual-energy X-ray absorptiometry (DEXA). Expression of ALPI II (p < 0.0001), osteopontin (p < 0.0001), RUNX2 (p < 0.0001), and osteocalcin (p < 0.0001) was upregulated after co-culture of MSC with CPC-P-15. BMD was decreased by 28.75% ± 2.6%. Pullout loads in untreated vertebrae were 1405 ± 6 N (p < 0.001) without augmentation, 2010 ± 168 N (p < 0.0001) after augmentation with CPC-P-15, and 2112 ± 98 N (p < 0.0001) with PMMA. In decalcified vertebrae, pullout loads were 828 ± 66 N (p < 0.0001) without augmentation, 1324 ± 712 N (p = 0.04) with PMMA, and 1252 ± 131 N (p < 0.0078) with CPC-P-15. CPC-P-15 induces osteoblastic differentiation of human MES and improves pullout resistance of pedicle screws in osteoporotic and non-osteoporotic bone.

• calcium phosphate cement
• collagen I mimetic P-15
• osteoporosis
• osteoporotic vertebral fractures
• polymethylmethacrylate

Oil-based calcium phosphate cement (Paste-CPC) shows not only prolonged shelf life and injection times, but also improved cohesion and reproducibility during application, while retaining the advantages of fast setting, mechanical strength, and biocompatibility. In addition, poly(L-lactide-co-glycolide) (PLGA) fiber reinforcement may decrease the risk for local extrusion. Bone defects (diameter 5 mm; depth 15 mm) generated ex vivo in lumbar (L) spines of female Merino sheep (2–4 years) were augmented using: (i) water-based CPC with 10% PLGA fiber reinforcement (L3); (ii) Paste-CPC (L4); or (iii) clinically established polymethylmethacrylate (PMMA) bone cement (L5). Untouched (L1) and empty vertebrae (L2) served as controls. Cement performance was analyzed using micro-computed tomography, histology, and biomechanical testing. Extrusion was comparable for Paste-CPC(-PLGA) and PMMA, but significantly lower for CPC + PLGA. Compressive strength and Young’s modulus were similar for Paste-CPC and PMMA, but significantly higher compared to those for empty defects and/or CPC + PLGA. Expectedly, all experimental groups showed significantly or numerically lower compressive strength and Young’s modulus than those of untouched controls. Ready-to-use Paste-CPC demonstrates a performance similar to that of PMMA, but improved biomechanics compared to those of water-based CPC + PLGA, expanding the therapeutic arsenal for bone defects. O, significantly lower extrusion of CPC + PLGA fibers into adjacent lumbar spongiosa may help to reduce the risk of local extrusion in spinal surgery.

• PMMA
• Young’s modulus
• calcium phosphate bone cement
• compressive strength
• micro-CT
• oil-based
• ready-to-use
• sheep
• water-based

The economic burden of vertebral compression fractures (VCF) caused by osteoporosis was estimated at 37 billion euros in the European Union in 2010. In addition, the incidence is expected to increase by 25% in 2025. The recommendations for the therapy of VCFs (conservative treatment versus cement augmentation procedures) are controversial, what could be partly explained by the lack of standardized outcomes for measuring the success of both treatments. Consensus on outcome parameters may improve the relevance of a study and for further comparisons in meta-analyses. The aim of this study was to analyze outcome measures from frequently cited randomized controlled trials (RCTs) about VCF treatments in order to provide guidance for future studies.

We carried out a systematic search of all implemented databases from 1973 to 2019 using the Web of Science database. The terms “spine” and “random” were used for the search. We included: Level I RCTs, conservative treatment or cement augmentation of osteoporotic vertebral fractures, cited ≥50 times. The outcome parameters of each study were extracted and sorted according to the frequency of use.

Nine studies met the inclusion criteria. In total, 23 different outcome parameters were used in the nine analyzed studies. Overall, the five most frequently used outcome parameters (≥ 4 times used) were the visual analogue scale (VAS) for pain (n = 9), European Quality of Life–5 Dimensions (EQ-5D; n = 4) and Roland–Morris Disability Questionnaire (RMDQ, n = 4).

With our study, we demonstrated that a large inconsistency exists between outcome measures in highly cited Level I studies of VCF treatment. Pain (VAS), followed by HrQoL (EQ-5D) and disability and function (RMDQ), opioid use, and radiological outcome (kyphotic angle, VBH, and new VCFs) were the most commonly used outcome parameters.

The online version contains supplementary material available at 10.1186/s12891-021-04305-6.

• Citation density
• Osteoporosis
• Outcome measure
• Spine
• Vertebral compression fracture

• bone fillers
• filler material
• osteogenesis
• stentoplasty
• vertebral compression fracture

• Chronic Disease
• Humans
• United States

• Calcium phosphate cement
• Clinical studies
• Degradation behavior
• Large animal models
• Osseointegration

• Animals
• Apatites
• Biocompatible Materials
• Bone Cements
• Bone Regeneration
• Calcium Phosphates
• Humans
• Materials Testing

• Augmentation
• Bone cements
• Classification
• Pedicle screws
• Spine

• Calcium phosphate cement
• N-acetyl cysteine
• Osteogenesis
• Silk fibroin
• Wnt/ β-catenin

• Calcium phosphate cements
• Fiber-matrix bond strength
• PVA fiber
• Pull-out test

• BB-1
• BMP-2
• GDF5
• PLGA fiber-reinforced
• bioactive bone morphogenetic proteins
• brushite-forming calcium phosphate cement
• in vitro release

• Proximal humerus
• augmentation
• biomechanical testing/analysis
• calcium phosphate cement
• fracture
• nail fixation
• osteoporosis

• Aged
• Biomechanical Phenomena
• Bone Cements
• Calcium Phosphates
• Female
• Fracture Fixation, Intramedullary/methods
• Humans
• Humeral Fractures/surgery
• Male
• Materials Testing
• Mechanical Phenomena

• Absorbable cement
• Calcium phosphate
• Kyphoplasty
• Vertebral body stenting
• Vertebral fracture

• Cement embolism
• Complications
• Percutaneous vertebroplasty
• cushing's syndrome

• Calcium phosphate
• Hydroxyapatite
• Injectable bone cement
• Kyphoplasty
• Osteoporosis
• Strontium

• Bone morphogenetic protein
• Bone regeneration
• Calcium phosphate cement
• Kyphoplasty
• Large animal model sheep
• Osteoporotic vertebral fracture
• Vertebroplasty

• Bone morphogenetic protein 2
• Bone regeneration
• Calcium phosphate cement
• Growth factor
• Large animal model sheep
• Osteoporotic vertebral fracture

• Biocompatibility
• Bone marrow
• Calcium phosphate
• Polymethylmethacrylate
• Primary human osteoblast

• Bone regeneration
• Calcium phosphate cement
• Fiber reinforcement
• In vivo
• Large animal model sheep
• Vertebroplasty

• Animals
• Bone Cements/chemistry
• Bone and Bones/drug effects
• Calcium Phosphates/chemistry
• Compressive Strength
• Humans
• Hydrogen-Ion Concentration
• Materials Testing
• Powders
• Pressure
• Stress, Mechanical
• X-Ray Diffraction

• Vetenskapsrådet

• Material properties
• PMMA
• Poly-methyl-methacrylate
• Saline solution
• Stiffness reduction

• Bone marrow extrusion
• Brushite-forming calcium phosphate cement
• Cement injection
• Ex vivo
• High-viscosity PMMA cement
• In vivo
• Large animal model
• Sheep
• Vertebroplasty

• Calcium phosphate cement
• Large animal model
• Minimal-invasive
• Sheep
• Ventrolateral
• Vertebroplasty
• Void defect

• Intervertebral disc
• Kyphoplasty
• Minimally invasive
• PMMA bone cement
• Vertebral fracture

• Augmentation
• Classification
• Kyphoplasty
• Osteoporosis
• Trauma

Bone loss and fractures may call for the use of bone substituting materials, such as calcium phosphate cements (CPCs). CPCs can be degradable, and, to determine their limitations in terms of applications, their mechanical as well as chemical properties need to be evaluated over longer periods of time, under physiological conditions. However, there is lack of data on how the in vitro degradation affects high-strength brushite CPCs over longer periods of time, that is, longer than it takes for a bone fracture to heal. This study aimed at evaluating the long-term in vitro degradation properties of a high-strength brushite CPC in three different solutions: water, phosphate buffered saline, and a serum solution. Microcomputed tomography was used to evaluate the degradation nondestructively, complemented with gravimetric analysis. The compressive strength, chemical composition, and microstructure were also evaluated. Major changes from 10 weeks onwards were seen, in terms of formation of a porous outer layer of octacalcium phosphate on the specimens with a concomitant change in phase composition, increased porosity, decrease in object volume, and mechanical properties. This study illustrates the importance of long-term evaluation of similar cement compositions to be able to predict the material's physical changes over a relevant time frame.

• Biomechanical phenomena
• Bone fractures
• Cement extrusion
• Kyphoplasty
• Vertebroplasty

• Chronic pain
• discogenic pain
• epidural injections
• facet joint pain
• failed back surgery syndrome
• intrathecal therapies
• low back pain
• lumbar spine
• physical activity
• spinal cord stimulation

Calcium phosphate biocements based on calcium phosphate chemistry are well-established biomaterials for the repair of non-load bearing bone defects due to the brittle nature and low flexural strength of such cements. This article features reinforcement strategies of biocements based on various intrinsic or extrinsic material modifications to improve their strength and toughness. Altering particle size distribution in conjunction with using liquefiers reduces the amount of cement liquid necessary for cement paste preparation. This in turn decreases cement porosity and increases the mechanical performance, but does not change the brittle nature of the cements. The use of fibers may lead to a reinforcement of the matrix with a toughness increase of up to two orders of magnitude, but restricts at the same time cement injection for minimal invasive application techniques. A novel promising approach is the concept of dual-setting cements, in which a second hydrogel phase is simultaneously formed during setting, leading to more ductile cement–hydrogel composites with largely unaffected application properties.

• biodegradable
• biomaterials
• composites
• mineral