The use of fixation and arthroplasty in treating elderly patients with nondisplaced femoral neck fracture (FNF) remains controversial. The femoral neck system (FNS) is known to have relatively stronger axial and rotational stability compared with cancellous screw fixation. This study aimed to evaluate how effective internal fixation using a FNS is for non-displaced FNF in elderly patients.

All patients with nondisplaced (Garden I and II) FNF between July 2019 and November 2023 were eligible for osteosynthesis surgery at three institutions. Ninety-five patients (50 under 75 years of age and 45 over 75 years of age) who were treated with FNS with a follow-up period of more than 1 year were included. Clinical data (age, sex, direction, body mass index, injury mechanism, bone mineral density (BMD), and time to operation) were extracted from patient records. Institutional imaging software was used for radiographic analysis to evaluate surgical site complications at 1 year. Multivariate logistic regression analysis was performed to identify independent risk factors for reoperation.

The mean age of the younger group was 61.0 years, whereas that of the elderly group was 81.2 years. No significant differences were observed between the two groups except for BMD and time to operation. Three reoperations were observed in the younger group (6%), and four cases were observed in the elderly group (8.9%) (p = 0.894), and no significant difference in other surgical complications was observed between the two groups. BMD was identified as an independent risk factor for reoperation.

FNS may be used as an alternative to elderly and younger patients with nondisplaced FNFs. However, the reoperation rate may increase in severe osteoporosis patients with very low hip BMD.

This study aims to assess the biomechanical performance of the 7.3 mm fully threaded off-axis screw (7.3-FTOS) configuration in stabilizing vertical femoral neck fractures (FNSs), comparing its effectiveness with other fixation methods.

A vertical FNF model with an 80° Pauwels angle was simulated and stabilized using four internal fixation constructs: Three inverted cannulated compression screws (ICCS), 7.3 mm partially threaded off-axis screw (7.3-PTOS), 4.5 mm fully threaded off-axis screw (4.5-FTOS), and 7.3-FTOS. The fracture fixation models were developed, refined, and optimized using Geomagic for 3D reconstruction and surface smoothing, and SolidWorks for parametric modeling. Comparative finite element analysis was then conducted using Ansys to assess the biomechanical behavior of each fixation method.

The maximum femoral displacements for ICCS, 7.3-PTOS, 4.5-FTOS and 7.3-FTOS were 10.40 mm, 8.08 mm, 7.71 mm, and 7.15 mm, respectively. The peak internal fixation displacements were 9.76 mm, 7.55 mm, 7.25 mm, and 6.78 mm, respectively. The maximum gap displacement measured 2.73 mm, 1.19 mm, 0.94 mm, and 0.55 mm, respectively. The maximum displacement along the Z-axis, representing the shear force direction, was recorded as 2.93 mm, 2.69 mm, 2.66 mm, and 2.63 mm, respectively. The peak von Mises stress (VMS) values in the distal femur were 218.04 MPa, 121.99 MPa, 123.42 MPa, and 113.86 MPa, respectively. The peak VMS values of the internal fixation constructs were 10.40 mm, 8.08 mm, 7.71 mm, and 7.15 mm, respectively.

Finite element analysis results revealed that 7.3-FTOS configuration exhibited superior resistance to shear and rotational forces in vertical FNFs compared to ICCS, 7.3-PTOS, and 4.5-FTOS, demonstrating enhanced mechanical performance. These findings establish a foundation for advancing experimental investigations and potential future clinical translation.

While the Femoral Neck System (FNS) is increasingly utilized for the fixation of femoral neck fractures in elderly patients, studies comparing the device to the historical standard (that is, multiple cannulated screws) are lacking. The purpose of this study was to determine the risk of all-cause revision following fixation with the FNS device compared with multiple cannulated screws in patients ≥60 years of age with a femoral neck fracture.

Patients ≥60 years of age who underwent fixation of a femoral neck fracture with the FNS or 3 cannulated screws (2017 to 2022) were identified using the Kaiser Permanente Hip Fracture Registry. Exclusion criteria were polytrauma, pathologic fracture, open fracture, additional surgeries at other sites during the same hospital stay, and prior procedures on the affected hip. The primary outcome measure was all-cause revision surgery, and the secondary outcome measures were mortality, emergency department visits, and readmissions. Multivariable Cox proportional hazards or logistic regression was performed, controlling for a wide range of potential confounders.

A total of 352 FNS and 1,686 cannulated-screw repairs were included. The overall incidence of revision at 2 years was 4.0% and 4.8% for the FNS and cannulated-screw constructs, respectively. Mortality at 2 years was 23.6% and 25.2%, respectively. In the adjusted analysis, no difference in all-cause revision risk was observed when comparing the FNS to cannulated screws (hazard ratio [HR] = 0.92, 95% confidence interval [CI] = 0.50 to 1.71; p = 0.79). A subgroup analysis of procedures performed by surgeons who used both devices also did not demonstrate a difference in revision rates (HR = 0.91; 95% CI = 0.39 to 2.17; p = 0.84).

In this study of patients ≥60 years of age with a femoral neck fracture, the rates of all-cause revision and mortality were found to be similar between the FNS and multiple cannulated screws.

Therapeutic Level III . See Instructions for Authors for a complete description of levels of evidence.

To report outcomes of femoral neck fractures (FNFs) treated with Femoral Neck System (FNS) and to compare the risks of later conversion to arthroplasty for FNS and fixation with cannulated screws (CNSs).

A retrospective study.

A single-center study (Turku University Hospital, Finland).

Data on 51 patients with FNFs treated with FNS between January 1, 2019, and May 31, 2021, were retrospectively reviewed. In addition, data on 301 patients treated with cannulated screws were collected and analyzed in a previous study.

Patients with FNFs underwent osteosynthesis with FNS.

Patients' preoperative and postoperative radiographs were analyzed and measured to determine preoperative displacement, preoperative posterior tilt, and quality of reduction. Later conversion to arthroplasty and other reoperations were recorded. The risk of later conversion to arthroplasty was compared between the FNS group and CNS group.

The overall reoperation rate in the FNS group was 20%, and 16% of the patients treated with FNS underwent later conversion to arthroplasty. In the multivariate analysis, age, sex, and fracture displacement were not associated with increased risk of later conversion to arthroplasty. In comparison with fixation with cannulated screws, there was no statistically significant difference in the probability of later conversion to arthroplasty between the groups.

FNS seems to have a comparable reoperation rate and conversion-to-arthroplasty rate compared with the gold standard treatment.

III.

Despite several surgical options, there has yet to be a consensus on the best treatment for femoral neck fracture (FNF) due to higher complication rates compared to other bone fractures. This study aims to examine the possible consequences and solution suggestions of changing screws during surgery for various reasons in FNF surgical treatment from a biomechanical perspective.

FNF and treatment materials were analyzed biomechanically using a package program based on the finite element method (FEM). This study created a solid model with images of femur bone tomography. Dynamic hip screws (DHS), cannulated screws (CCS), and medial buttress plates (MBP) were obtained by making three-dimensional designs. The required elements for the models were assigned, and the material properties of the elements were defined. The solutions were obtained as crack distance and deformation results after defining the boundary conditions and applying the necessary loading.

The strain and crack distance values created by six models on the fracture line under different parameters were obtained, and the numerical results were evaluated. The DHS and CCS models produced the highest crack distance and deformation values when all screws were loose. The lowest values were obtained in the intact-85 model when all CCS were tight. When the results are evaluated, it is seen that the MBP has a decreasing effect on the results. Mechanical evaluation of six different options used in femoral neck fractures was performed. 85 mm CCS applied to our standard model gave the best results, while the use of 80 mm CCS in the same model showed promising results compared to other models. It is understood that CCS have the best stability even in loosening models with the medial support plate. Different models are from intact-85 mm DHS+1CS+MBP to DHS+1CS, which was worked with LSR+USR-2, according to decreasing stability.

This study offers various biomechanical solutions to possible intraoperative problems in FNF treatment. The following results were obtained from the study data. When the CCS needs to be lengthened or replaced, it is appropriate to use the CCS with the MBP. A single anti-rotation screw is sufficient for lag screw extensions of the DHS plate, and the MBP may be a savior procedure in surgery.

Osteonecrosis, also referred to as avascular necrosis, is a disease characterized by necrosis or death of a bone secondary to impairment in blood supply. The condition affects the epiphyseal ends of the bones such as the femur and the humerus, but it can also involve the metacarpal and metatarsal bones, the patella, the knee, the vertebrae, and the jaw. A plethora of inflammatory, autoimmune, hematological, thrombotic, and vascular diseases can lead to osteonecrosis. Corticosteroids are intimately linked to the development of osteonecrosis. The frequent use of systemic corticosteroids in patients with asthma, eczema, nasal polyposis, sinusitis, urticaria and angioedema, or anaphylaxis makes this disease of great relevance to the practicing allergist and pulmonologist. Untreated, bone necrosis leads to frustrated bone remodeling and angiogenesis, leading to subchondral fractures and collapse of the articular heads of the bones, and culminating in debilitating osteoarthritis, often requiring arthroplasty. Recent studies have shed light on the molecular mechanisms underlying osteonecrosis and on the role of glucocorticoids. The gold standard test in patients suspected of having the disease is magnetic resonance imaging scanning, with plain radiographs having a lower sensitivity and specificity. Early diagnosis and intervention are essential. The allergist should avoid the frequent use of glucocorticoids and consider early introduction of steroid-sparing alternatives for asthma or sinusitis. Smoking and alcohol ingestion need to be addressed, and the management of glucocorticoid-induced osteoporosis may be helpful. It is essential for allergists to familiarize themselves with the disease and its diagnosis and to consider early referral to an orthopedic surgeon for surgical intervention.

This study aimed to evaluate the clinical effectiveness of the femoral neck system (FNS) compared to four cannulated compression screws (CCSs) for managing Pauwels type III femoral neck fractures in young patients.

A retrospective analysis was conducted on young patients with Pauwels type III femoral neck fractures treated at our hospital from January 2021 to December 2022. Patients were categorized into two groups based on their respective internal fixation methods: the FNS group (32 cases) and the CCSs group (41 cases). Various demographic and clinical variables, including age, gender, fracture side, mechanism of injury, Garden classification, and time interval between injury and surgery, were collected. Comparisons were made between the two groups regarding operative duration, intraoperative blood loss, length of hospital stay, hospitalization expenses, time to fracture healing, and Harris hip score at one year post-surgery. Additionally, postoperative complications such as wound infections, nonunion, femoral neck shortening, avascular necrosis of the femoral head, and hardware failure were analyzed. Follow-up duration ranged from 12 to 24 months for all patients.

There were no significant differences between the FNS and CCSs groups in terms of demographic characteristics, fracture characteristics, time to fracture healing, duration of hospital stay, and Harris hip score at one year post-surgery (p > 0.05). However, the CCSs group exhibited significantly shorter operative time, reduced intraoperative blood loss, and lower hospitalization costs compared to the FNS group (p < 0.05). Patients treated with FNS had longer operative durations (82.33 ± 28.85 min vs. 66.58 ± 14.38 min, p = 0.006), higher blood loss (106.67 ± 65.83 mLvs.70.00 ± 27.39 mL, p < 0.001), and increased hospitalization expenses (58,345.98 ± 3706.57 RMB vs. 35,427.63 ± 3019.30 RMB, p < 0.0001). The incidence of postoperative complications was 21.8% in the FNS group and 26.8% in the CCSs group (p > 0.05), with no significant differences observed in the rates of wound infections, femoral neck shortening, femoral head necrosis, nonunion, and hardware failure between the two groups (p > 0.05).

In the management of Pauwels type III femoral neck fractures in young patients, FNS demonstrates clinical efficacy comparable to CCSs. However, considering factors such as operative time, intraoperative blood loss, and hospitalization costs, CCSs may be preferred.

Hip fractures, particularly femoral neck and intertrochanteric fractures, represent approximately 6.37 % of all fractures, with incidence rates showing an upward trend annually.

This report presents a case of a 55-year-old female with a femoral neck fracture who underwent internal fixation. One-year post-surgery, the patient continued to experience hip pain, and computed tomography (CT) scans revealed non-union of the fracture. The patient received an integrated treatment approach combining traditional Chinese and Western medicine, involving the alternating administration of osteopeptide tablets and Guijia Jiangu capsules, a proprietary herbal formulation. No additional pharmacological or surgical interventions were employed. Seven months after initiating the treatment, digital radiography (DR) examinations showed that the fracture had largely healed. At the seven-month follow-up, and nearly four years thereafter, the patient reported no discomfort in the hip region. Subsequent DR examinations revealed no signs of avascular necrosis of the femoral head, and no adverse events were noted. The internal fixation device was removed five years post-fracture.

The results indicate that integrated traditional Chinese and Western medicine may effectively treat non-union after internal fixation of femoral neck fractures, though further studies are warranted to confirm these outcomes.

The optimal treatment for Pauwels type III femoral neck fractures remains contentious. We aim to compare the biomechanical properties of three inverted cannulated compression screw (ICCS), femoral neck system (FNS), and percutaneous compression plate (PCCP) to determine which offers superior stability for unstable femoral neck fractures.

Finite element analysis and artificial bone models were used to establish Pauwels III femoral neck fracture models. They were divided into ICCS, FNS, and PCCP groups based on respective internal fixation assemblies. The models were subjected to vertical axial loads (2100 N) and torsional forces (10 N × mm) along the femoral neck axis in the finite element analysis. The primary outcomes such as the Z axis fragmentary displacements, as well as displacements and the von Mises stress (VMS) distributions of internal fixations, were analyzed. Additionally, the artificial bones were subjected to progressively increasing vertical axial pressures and torsional moments at angles of 2°, 4°, and 6°, respectively. The vertical displacements of femoral heads and the required torque values were recorded.

Finite element analysis revealed that under single-leg stance loading, the maximum Z-axis fragmentary displacements were 5.060 mm for ICCS, 4.028 mm for FNS, and 2.796 mm for PCCP. The maximum displacements of internal fixations were 4.545 mm for ICCS, 3.047 mm for FNS, and 2.559 mm for PCCP. Peak VMS values were 512.21 MPa for ICCS, 242.86 MPa for FNS, and 413.85 MPa for PCCP. Under increasing vertical loads applied to the artificial bones, the average vertical axial stiffness for the ICCS, FNS, and PCCP groups were 244.86 ± 2.84 N/mm, 415.03 ± 27.10 N/mm, and 529.98 ± 23.08 N/mm. For the torsional moment tests, the PCCP group demonstrated significantly higher torque values at 2°, 4°, and 6° compared with FNS and ICCS, with no significant difference between FNS and ICCS (P > 0.05).

Finite element analysis and artificial bone models indicated that PCCP offers the best compressive and rotational stability for fixing Pauwels type III femoral neck fractures, followed by FNS and then ICCS. No significant difference in rotational resistance was observed between FNS and ICCS in synthetic bones. Level of Evidence Level 5.

Femoral neck fractures (FNF) represent a significant challenge in orthopedic practice, demanding prompt intervention to restore function and mobility in affected individuals. Numerous surgical interventions have been developed to address these fractures, including internal fixation with devices such as the Femoral Neck System (FNS, DePuy Synthes, Inc., West Chester, PA, USA). However, the optimal fixation system remains unclear. Understanding the postoperative outcomes associated with these interventions is crucial for optimizing patient care and informing treatment decisions.

This PRISMA-compliant systematic literature review evaluates the efficacy and safety of the Femoral Neck System relative to other operative treatment options. Clinical and safety outcomes included mortality, perioperative complications, postoperative complications at 1 year, and reoperation.

A total of 117 studies with 68,567 patients with FNF treated with internal fixation were identified. Of these, thirteen included FNS as a treatment arm (1078 patients). Due to heterogeneity in study designs and populations, only the eleven studies that directly compared FNS to other operative treatments, and 2 non-comparative studies that treated with FNS were included in the systematic review. Seven of the eleven included studies had high risk of bias, 2 had moderate risk of bias, and 2 had low risk of bias. FNS groups had similar or significantly lower incidences of postoperative complications, reoperations, and mortality compared to cannulated screw, cancellous screw, or dynamic or sliding hip screw groups in all studies.

FNS can be a safe and effective operative treatment option for FNF. Safety outcomes and reoperation rates are comparable between patients treated with FNS and patients treated with cannulated screws, cancellous screws, and dynamic or sliding hips screws. Future prospective, controlled studies are needed to confirm the safety and efficacy of FNS relative to other operative treatment options.

The primary treatment of femoral neck fracture in young adults is internal fixation. The high complication rate after femoral neck fracture greatly affects the life of patients. There are many internal fixation devices for femoral neck fracture, but each has its advantages and disadvantages. Our aim was to determine the best internal fixation for young people with femoral neck fractures.

We searched 5 databases from January, 2016 to December, 2023. Randomized controlled trials and cohort studies that met the inclusion criteria were assessed for quality using the RoB.2 and ROBINS-I scales, respectively. The network meta-analysis was conducted within a Bayesian framework utilizing a random effect model. Data analysis was performed using the "multinma" package within the R 4.2.0 software.

A network meta-analysis of 34 studies involving 2291 patients was conducted. Results indicated that the inverted triangular cannulated screws demonstrated the lowest intraoperative bleeding volume (surface under the cumulative ranking curve [SUCRA] = 0.8732) based on the SUCRA. The medial buttress plate (MBP) exhibited superior efficacy in improving the Harris hip score (SUCRA = 0.8465), reducing complications (SUCRA = 0.9251), and accelerating fracture healing time (SUCRA = 0.8111). Additionally, the femoral neck system was ranked highest in terms of operation time (SUCRA = 0.7749) and femoral neck shortening (SUCRA = 0.7933).

This network meta-analysis findings indicated that MBP resulted in superior postoperative hip function, reduced complication rate, faster fracture healing time. Considering the good physical condition of young adults, surgeon may consider utilizing MBP to achieve improved postoperative outcomes.

The FNS System DePuy Synthes® (EEUU, 2018) represents a recent alternative treatment for the fixation of femoral neck fractures, providing biomechanical advantages with respect to cannulated screws (3 CS). The objective of this study is to compare the clinical results of both fixation methods.

A retrospective collection of the 36 subcapital fractures treated with the FNS system was carried out compared with a retrospective search of the last 35 patients treated with 3 CS. Age, sex, fracture pattern, delay until the intervention, length of intervention, hospital length stay, and haemoglobin loss were analyzed. In addition, the rate of avascular necrosis, nonunion, symptomatic femoral neck shortening, and material protrusion with or without its removal were recorded during a minimum follow-up of 6 months.

No significant differences were found in age (p-value 0.32), fracture patterns (p-value 0.77), surgical delay (p-value 0.28), surgical time (p-value 0.226), length of hospital stay (p-value 0.921) and blood loss (p-value 0.086) between the two groups. A significantly higher overall complication rate was observed in the group treated with cannulated screws (p-value 0.004). Analysed separately, a higher rate of avascular necrosis, symptomatic shortening of the femoral neck, protrusion of the osteosynthesis material with or without removal was observed in the group treated with cannulated screws.

The FNS system represents a safe and reproductible alternative for the fixation of femoral neck fractures, showing non-inferior outcomes to treatment with cannulated screws.

Despite the explicit biomechanical advantages associated with FNS, it is currently inconclusive, based on the existing literature, whether Femoral Neck System (FNS) outperforms Cannulated cancellous screws (CSS) in all aspects. Due to variances in bone morphology and bone density between the elderly and young cohorts, additional research is warranted to ascertain whether the benefits of FNS remain applicable to elderly osteoporosis patients. This study aimed to investigate the biomechanical properties of FNS in osteoporotic femoral neck fractures and propose optimization strategies including additional anti-rotation screw.

The Pauwels type III femoral neck fracture models were reconstructed using finite element numerical techniques. The CSS, FNS, and modified FNS (M-FNS) models were created based on features and parameterization. The various internal fixations were individually assembled with the assigned normal and osteoporotic models. In the static analysis mode, uniform stress loads were imposed on all models. The deformation and stress variations of the femur and internal fixation models were recorded. Simultaneously, descriptions of shear stress and strain energy were also incorporated into the figures.

Following bone mass reduction, deformations in CSS, FNS, and M-FNS increased by 47%, 52%, and 40%, respectively. The equivalent stress increments for CSS, FNS, and M-FNS were 3%, 43%, 17%, respectively. Meanwhile, variations in strain energy and shear stress were observed. The strain energy increments for CSS, FNS, and M-FNS were 4%, 76%, and 5%, respectively. The shear stress increments for CSS, FNS, and M-FNS were 4%, 65% and 44%, respectively. Within the osteoporotic model, M-FNS demonstrated the lowest total displacement, shear stress, and strain energy.

Modified FNS showed better stability in the osteoporotic model (OM). Using FNS alone may not exhibit immediate shear resistance advantages in OM. Concurrently, the addition of one anti-rotation screw can be regarded as a potential optimization choice, ensuring a harmonious alignment with the structural characteristics of FNS.

Internal fixation has been established as a treatment of choice in relatively young patients with femoral neck fractures. Due to the characteristics of femoral neck anatomy and blood supply, complications such as malunion, nonunion, avascular necrosis, and femoral neck shortening can occur after internal fixation of femoral neck fractures. Unlike other complications such as avascular necrosis or nonunion, femoral neck shortening has not been relatively well studied. This study aimed to investigate the risk factors and clinical outcomes of femoral neck shortening after internal fixation of femoral neck fractures.

From June 2012 to July 2022, among 102 patients who underwent internal fixation of femoral neck fractures, 94 patients who met inclusion and exclusion criteria were retrospectively analyzed. Internal fixation of the femoral neck was done with cannulated compression screws or a femoral neck system. Patients were divided into 2 groups; femoral neck shortening (≥ 5 mm) and no shortening (< 5 mm) according to measurement on follow-up hip anteroposterior (AP) simple radiographs compared with postoperative hip AP simple radiographs. Demographic and radiographic data were compared between the 2 groups. The modified Harris Hip Score (mHHS) and a visual analog scale (VAS) were used to evaluate the clinical outcomes.

Among 94 patients, femoral neck shortening was observed in 33 (35.1%). In chi-square test, Pauwels angle, Garden type III or IV (displacement), and cortical comminution were significantly correlated with neck shortening (p < 0.05). In the multifactorial logistic regression test, cortical comminution was significantly correlated with femoral neck shortening (p < 0.01). The shortening group showed significantly lower clinical scores in terms of mHHS and VAS (p < 0.01).

The femoral neck shortening group showed significantly lower clinical scores of mHHS and VAS than the no-shortening group. The presence of cortical comminution in preoperative hip computed tomography is a risk factor of femoral neck shortening after internal fixation of femoral neck fractures.

Displaced femoral neck fractures are associated with a high revision rate. The new femoral neck system(FNS) offers advantages in fixation stability, potentially reducing the need for revision. The purpose of this study was to compare the revision rate of patients with different reduction quality treated with the FNS and cannulated screws (CS).

This retrospective study included patients with Garden III or IV femoral neck fractures who underwent osteosynthesis in a level 1 trauma center between July 2019 and June 2023. A total of 141 cases met the inclusion criteria and received treatment with either the FNS (N = 65) or CS (N = 76). The quality of fracture reduction, surgical complications (such as femoral neck shortening, avascular necrosis of femoral head, nonunion of fracture, implant failure and withdrawal), revision surgery and the reasons for revision were analyzed.

The mean age of the 141 cases was 52.0 years (range 18-65); with sixty-five cases being male (46.1%). Eighty-four fractures (59.6%) were classified as Garden type III. Reduction quality was good in 71 cases (50.4%) and fair in 70 cases. The mean follow-up period was 25.9 months (range 12-46). A total of 26 cases(18.4%) underwent revision surgery. The revision rate in cases with good reduction was 11.3% (8/71 cases), with seven cases (four hardware removal and three arthroplasty) in the CS group and one case (arthroplasty for fracture nonunion and implant failure) in the FNS group, a significant difference was found between the two groups(P = 0.041). Among the 18 cases (25.7%, 18/70) with fair reduction who underwent revision surgery, nine cases (six hardware removal and three arthroplasty) in the CS group, and nine cases (arthroplasty for implant failure and cut-out) in the FNS group, and there was no significant difference between the two groups (P = 0.672). The total revision rate between the FNS group (15.4%, 10/65) and the CS group (21.1%, 16/76) was not significantly different (P = 0.387).

The total revision rate between the FNS and CS group showed no difference. However, in cases with good reduction, the revision rate was lower in the FNS group compared to the CS group.

This study aimed to compare the clinical outcomes and differences in biomechanical characteristics between the femoral neck system (FNS) and cannulated cancellous screws (CCSs) in the treatment of femoral neck fractures.

This study retrospectively analysed a cohort of 38 registered cases of femoral neck fractures treated surgically with either the FNS (n = 17) or CCSs (n = 21) between January 2020 and December 2023. Indicators such as fluoroscopy frequency, length of hospital stay, and fracture healing time were compared between the two groups. Functional status was evaluated via the Harris hip score (HHS) and visual analogue scale (VAS), whereas prognosis was assessed based on changes in the neck shaft angle and femoral neck shortening. Additionally, six sets of femoral neck fracture models were developed based on Pauwels angles of 30°, 40°, 50°, 60°, 70°, and 80°. Two experimental groups, FNS and CCS, were established, and a joint reaction force of 1800 N was applied to the proximal femur. The displacement, stress, and stiffness of the components of interest in the different models were tested and compared.

The distributions of all the baseline characteristics were similar between the two groups (p > 0.05). The FNS group presented significantly shorter fluoroscopy frequency, length of hospital stay, and fracture healing time (p < 0.05). Harris and VAS scores were higher in the FNS group than in the CCS group (p < 0.05). Postoperative changes in the neck shaft angle and femoral neck shortening were significantly lower in the FNS group than in the CCS group (p < 0.05). The results of the finite element analysis indicated that the maximum stress on the femoral head and varus angle were generally lower in the FNS group than in the CCS group and that the maximum displacement of the femoral head and FNS was generally lower in the FNS group than in the CCS group. However, the superiority of FNS over CCS decreased with increasing Pauwels angle. Additionally, the effectiveness of FNS in limiting displacement of the femoral neck upper wall was not as favourable as that of CCS.

The treatment of femoral neck fractures with FNS is superior and contributes to improved hip joint function. Biomechanical research has confirmed its structural stability and advantages in resisting femoral head varus. However, challenges to its fixation efficacy persist, particularly at higher Pauwels angles.

Prospective study of femoral neck system (FNS) vs. cannulated compression screw (CCS) fixation has not been appropriately reported. We prospectively investigate the efficacy of FNS vs. CCS fixation combined with ERAS in the treatment of unstable intracapsular FNF. 70 consecutive patients with unstable intracapsular femoral neck fracture met the inclusion criteria were randomly divided into FNS group and CCS group (each 35 cases). ERAS was applied in both groups. The perioperative period and follow-up results were compared. The operation time, fluoroscopy time, fracture reduction quality and follow-up time were not significantly different between the two groups (P > 0.05). The blood loss in the FNS group was significantly more than that in CCS group whereas the time to start weight-bearing, fracture healing time, internal fixation failure in the FNS group were significantly less than those in the CCS group (P < 0.05). The neck shortening and revision surgery of the FNS group showed a trend of superiority to CCS group but the difference was not significantly different (P > 0.05). The AVN in the two groups was similar. At the last follow-up, the Harris hip score in the FNS group was higher than that in the CCS group (P < 0.05). Hence, FNS fixation with ERAS for FNF can provide earlier weight-bearing, fewer complications related to the implant, faster healing and better functional recovery than CCS fixation with ERAS, which is consistent with the better biomechanical properties of FNS.

This study aimed to assess the efficacy of three different fixation methods in treating femoral neck fractures in young patients.

A retrospective analysis was conducted on 35 young patients with femoral neck fractures who underwent surgical treatment. Among them, 16, 12, and 7 patients underwent fixation with three cannulated compression screws (3CS), the femoral neck system (FNS), and the compound compression system (CCS), respectively. Data, including fracture classification, injury-to-surgery time, surgery duration, intraoperative blood loss, fluoroscopy instances, fracture healing time, complications, and Harris score at the final follow-up, were collected and analyzed to compare clinical outcomes among the three fixation methods.

All patients were followed for at least 6 months, exhibiting no significant differences in age, gender, injury side, fracture type, or injury-to-operation time among the three groups (P > 0.05). The FNS and CCS groups exhibited shorter operation durations and fewer intraoperative fluoroscopy instances compared to the 3CS group (P < 0.01). Despite the minimally invasive nature of 3CS, the FNS and CCS groups experienced higher intraoperative blood loss (P < 0.01). During follow-up, only one patient with 3CS fixation developed nonunion. Additionally, patients treated with 3CS demonstrated a higher incidence of femoral head necrosis and severe femoral neck shortening than the FNS and CCS groups. Excluding patients with combined nonunion, no significant difference in mean fracture healing time was observed among the three groups (P > 0.05). At the last follow-up, the FNS and CCS groups showed higher Harris scores (P < 0.05).

Both FNS and CCS are effective internal fixation systems for the treatment of femoral neck fractures in young patients, yielding more satisfactory clinical functional outcomes than 3CS. Comparatively, the CCS system presents a higher risk of iatrogenic rotation of the proximal fracture segment. Therefore, we advocate the insertion of two to three 2.5 mm Kirschner wires from the upper edge of the femoral neck along the axial direction before CCS lag screw insertion to resist iatrogenic rotational stress.

Addressing subcapital fractures of the femur poses a substantial clinical challenge, complicated by the diverse range of available osteosynthesis materials. This study is dedicated to a comprehensive analysis of the clinical and radiological implications linked with the implementation of the Femoral Neck System (FNS) in osteosynthesis procedures. A descriptive study was conducted involving patients who underwent osteosynthesis for subcapital fractures of the femur utilizing the FNS during the period from 2019 to 2022. The investigation encompassed various facets, including the classification of fractures according to the Garden and Pauwells classifications, criteria for achieving precise reduction based on the Garden criteria and Tip Apex Distance (TAD). At the one-year follow-up, factors such as fracture consolidation, loss of reduction, fracture collapse, complications, and functional outcomes were evaluated utilizing the Harris Hip Score (HHS) scale. The study cohort included a total of 26 patients, among whom 22 exhibited non-displaced subcapital femur fractures categorized as Garden I and II. Successful reduction was accomplished in 23 cases, in which 24 cases (92.3%) displayed a TAD measurement below 25 mm. According to the HHS, patients achieved an average score of 90.9 (ranging from 63 to 100) following the surgical intervention, with predominantly "excellent" and "good" outcomes. The outcomes derived from our investigation corroborate the viability of the Femoral Neck System (FNS) as a reliable option for osteosynthesis in femoral neck fractures. The results obtained are comparable to those achieved with other available implants, as highlighted by previous studies.

The purpose of this study was to compare the outcomes of femoral neck shortening between the femoral neck system (FNS) and the cannulated cancellous screws (CCS) for displaced femoral neck fractures in young adults PATIENTS AND METHODS: In this retrospective analysis, 225 patients aged 18-65 years with displaced femoral neck fracture were divided into two groups according to internal fixation: 135 patients in the FNS group and 90 patients in the CCS group. The length of hospital stay, duration of surgery, intraoperative blood loss, quality of reduction, extent of femoral neck shortening, incidence of femoral neck shortening, femoral neck shortening at each follow-up visit, Harris hip score (HHS), reoperation, and complications were compared between the two groups.

The median follow-up time was 28.2 (26.0, 31.2) months in the FNS group and 30.2 (26.3, 34.7) months in the CCS group. The follow-up time, age, sex distribution, body mass index (BMI), mechanism of injury, injured side, length of hospital stay, time from injury to surgery, and fracture classification were similar between the groups. Duration of surgery was longer in the FNS group (65.0 (55.0, 87.0) min versus 55.0 (50.0, 65.0) min, P<0.001); intraoperative blood loss was greater in the FNS group (50.0 (20.0, 60.0) ml versus 20.0 (10.0, 35.0) ml, P<0.001). Femoral neck shortening was 2.4 (1.0, 4.5) mm in the FNS group versus 0.6 (0.0, 2.6) mm in the CCS group at 1 month postoperatively (P<0.001); 3.7 (1.8, 6.4) mm in the FNS group versus 1.2 (0.6, 3.8) mm in the CCS group at 3 months (P<0.001); 4.1(2.4, 7.7) mm in the FNS group versus 2.3 (1.1, 4.4) mm in the CCS group at 6 months (P<0.001); 4.2 (2.6, 7.7) mm in the FNS group versus 2.6 (1.3, 4.6) mm in the CCS group at 12 months (P<0.001); and 4.5 (2.8, 8.0) mm in the FNS group versus 2.8 (1.5, 4.8) mm in the CCS group at 18 months (P<0.001). The two groups showed no significant differences in HHS, reoperation, and reduction quality.

Compared to CCS, FNS is deficient in preventing femoral neck shortening. Future research should focus on improving FNS in terms of preventing femoral neck shortening.

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).

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.

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.

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.

To investigate the efficacy of using pre-sliding technique to prevent postoperative shortening of displaced femoral neck fracture fixed with femoral neck system (FNS).

Retrospective analysis of 110 cases of displaced femoral neck fracture treated with femoral neck system from September 2019 to November 2022 in our center, which were divided into 56 cases in the pre-sliding group and 54 cases in the traditional group. The baseline data such as gender, age, side, mechanism of injury, fracture type, operation time, intraoperative bleeding were recorded and compared between the two groups, and the quality of fracture reduction, shortening distance, Tip Apex Distance (TAD), union time, Harris score of the hip were also compared between the two groups.

The TAD value of the pre-sliding group was smaller than that of the traditional group, and the difference was statistically significant (P < 0.001). The shortening distance in both groups on postoperative day 1 was smaller in the pre-sliding group than in the traditional group, but the difference was not statistically significant (P = 0.07), and the shortening distance was smaller than in the traditional group at 1, 3, 6, and 12 months postoperatively, and the difference was statistically significant (all P < 0.001). Of the 110 cases, 34 (30.9%) had moderate or severe shortening, of which 24 (44.4%) were in the traditional group and 10 (17.9%) in the pre-sliding group, and the difference was statistically significant (P < 0.001), and the Harris score at 1 year, which was higher in the pre-sliding group than in the traditional group, and the difference between the two groups was statistically significant (P < 0.001). There was no statistically significant difference in the comparison of baseline data such as gender, age, side, mechanism of injury, fracture type, operation time, intraoperative bleeding, and quality of reduction between the two groups (all P > 0.05), and no statistically significant difference in fracture healing time between the two groups (P = 0.113).

The use of the pre-sliding technique of displaced femoral neck fracture fixed with FNS reduces the incidence of moderate and severe shortening, improves the postoperative TAD value, and improves the hip function scores, with a satisfactory midterm efficacy.

The purpose of this study is to evaluate the effect of pre-sliding of the femoral neck system (FNS) in the prevention of postoperative femoral neck shortening in femoral neck fractures.

This study was designed to retrospectively analyze data from 109 patients with femoral neck fractures who were admitted to a Level I trauma center between April 2020 and June 2022. Of these patients, 90 were followed up for more than 12 months. The study included 52 males and 38 females, with 35 cases of Garden I and II fractures and 55 cases of Garden III and IV fractures. The Harris Hip Score at 12 months postoperatively were recorded. The patients were divided into two groups based on their surgical records and postoperative radiography: the Pre-sliding group and the No-pre-sliding group. The purpose of this study is to analyze the role of pre-sliding in preventing femoral neck shortening, fracture healing time, degree of postoperative shortening, complications, and Harris Hip Score, and to make a comparison between the two groups.

All 90 patients were followed up for over one year after surgery. A statistically significant difference was observed in the preoperative Garden classification (P < 0.05). At 1 year after the operation, the shortening distance was 6.5 ± 6.4 mm in the No-pre-sliding group and 3.9 ± 3.4 mm in the Pre-sliding group. The Harris Hip Score were 88.7 (79.8, 93.5) in the No-pre-sliding group and 94.8 (87.7, 96.9) in the Pre-sliding group, with a statistically significant difference between the two groups (P < 0.05). Shortening was concentrated at 3 months postoperatively and reached a stable state within 6 months, with less persistent shortening occurring after 6 months. There was no statistically significant difference in the preoperative baseline data.

Pre-sliding of the FNS prevents postoperative shortening of the femoral neck and improves hip function as measured by the Harris Hip Score.

Femoral neck fractures in physiologically young patients typically occur from high-energy axial loading forces through the thigh with the hip in an abducted position. These fractures have a high rate of associated head, chest, abdominal, and musculoskeletal injuries. High-energy hip fractures differ from traditional geriatric hip fractures regarding incidence, mechanism, management algorithms, and complications. After adequate resuscitation, goals of treatment include anatomic reduction and stable fixation while maintaining vascularity of the femoral head, which can be achieved through a variety of different techniques. Prompt recognition and treatment of these fractures is crucial to achieve a successful outcome because these injuries are often associated with complications such as osteonecrosis, fixation failure, and nonunion.

Femoral neck fractures need to be treated in their early stages with accurate reduction and stable fixation to reduce complications. The authors compared the early radiologic outcomes of femoral neck fractures treated with the recently introduced Femoral Neck System (FNS, Depuy-Synthes) with conventional cannulated screws (CS) in a multicenter design. Furthermore, the factors associated with early failure after FNS were analyzed.

The FNS group included 40 patients treated between June 2019 and January 2020, and the CS group included 65 patients treated between January 2015 and May 2019. The operation was performed in 3 university hospitals. Patient demographics, fracture classification, postoperative reduction quality, sliding distance of FNS or CS, union and time to union, and complication rates were examined. Logistic regression analysis was performed on candidate factors for early failure of the FNS group.

The FNS group had a 90% union rate and a mean time to union of 4.4 months, while the CS group had similar results with an 83.1% union rate and a mean time to union of 5.1 months. In the subgroup analysis of Pauwels type III fractures, the union rates were 75.0% and 58.8% in the FNS and CS groups, respectively, and the time to union was significantly shorter in the FNS group with 4.8 months compared to 6.8 months in the CS group. Early failure rate within 6 months of FNS fixation was observed to be 10%, which included 3 reduction failures and 1 excessive sliding with a broken implant. Risk factors for early failure after FNS were identified as displaced fractures (Garden classification type III or IV), poor reduction quality, longer tip-apex distance, greater sliding distance, and 1-hole implants, of which sliding distance was the only significant risk factor in multivariate analysis.

In femoral neck fractures, FNS and CS did not show significant differences for short-term radiologic results. FNS resulted in shorter operative time than cannulated screw fixation and favorable outcomes in Pauwels type III femoral neck fractures. The FNS could be considered a reliable and safe alternative to CS when treating femoral neck fractures.

The aim of the study is to determine the revision ratio after implantation of the femoral neck system (FNS) for the treatment of femoral neck fractures. A retrospective single center cohort analysis with a total of 71 patients who underwent the implantation of the FNS between December 2019 and December 2021, was performed. 31 males and 40 females were included. There was no exclusion based on BMI, ASA score, Garden classification or Pauwels classification. Primary outcome was the revision rate after FNS implantation. Secondary outcomes comprise the reason for revision surgery as well as the time toward revision surgery and the 30-day mortality. The revision ratio was 11 out of 71 patients (15.5%) with an average time to revision surgery of 10 months. Most common reason for revision was avascular necrosis (AVN) in 45.5%. Other reasons for revision surgery were implant failure due to a secondary fall on to the hip with the FNS implant in place, cut-out, cut-through and malunion in respectively 27.3%, 9%, 9% and 9% of the revision patients. The one- hole plate was used in 72% of the patients. Mean follow-up was 18.07 months (range 6-30 months). Full weight bearing instruction was given to 85.9% of the patients. Partial weight bearing in 14.1% of the patients. In conclusion, the FNS has similar revision ratio when used for femoral neck fractures compared to cannulated screw fixation in literature. The predominant reason for revision is AVN and implant failure with no difference between the use of the one- or-two-hole plate in this study.

The femoral neck system (FNS) represents an emerging fixation system designed for the management of femoral neck fractures. This innovative system combines the mechanical benefits of compression and anti-rotation properties in internal fixation. Biomechanical studies have demonstrated the superior axial and rotational stability of the FNS implant when compared to traditional cannulated screws and dynamic hip screw. Despite these promising mechanical advantages, there is currently a limited body of literature addressing the factors contributing to FNS failure. A thorough assessment of the safety and outcomes associated with this novel implant is essential.

In this context, we present three cases wherein FNS failure occurred, aiming to elucidate the potential causes behind these failures, and had to undergo either an implant removal or bipolar hemiarthroplasty.

While considering the femoral neck system as the implant of choice, we should consider the age, injury to surgery time, and the location of the fracture line. However, we cannot conclusively ascertain whether age contributes independently to the risk of failure.

As a novel internal fixation for femoral neck fractures, the femoral neck system has some advantages for young Pauwels type III femoral neck fractures without clear biomechanical effects and mechanisms. Thus, the objection of the study is to realize the biomechanical effects and mechanism of FNS cannulated screws on treating young patients with Pauwels type III femoral neck fractures compared to cannulated screws which are commonly used for femoral neck fractures by finite element analysis.

Firstly, the model of young Pauwels type III femoral neck fractures, femoral neck system (FNS), and three cannulated screws (CS) arranged in an inverted triangle were established, and the internal fixations were set up to fix young Pauwels type III femoral neck fractures. Under 2100 N load, the finite element was performed, and the deformation, peak von Mises stress (VMS), and contact at fracture segments were recorded to analyze the biomechanical effects and mechanism of FNS and three-CS fixing young Pauwels type III femoral neck fractures.

Compared to three-CS, the deformation of the whole model, internal fixation, and fracture segments after FNS fixation were lower, and the peak VMS of the whole model and the internal fixation after FNS were higher with lower peak VMS of the distal femur and the fracture segments. With a sticking contact status, the contact pressure at fracture segments after FNS fixation was lower than that of three-CS.

FNS can provide better mechanical effects for young patients with Pauwels type III femoral neck fractures, which may be the mechanical mechanism of the clinical effects of FNS on femoral neck fracture. Although there is high stress on FNS, it is still an effective and safe internal fixation for young patients with Pauwels type III femoral neck fractures.

Femoral neck fractures in older adult patients are a major concern and often necessitate surgical intervention. This study compared the clinical outcomes of 2 surgical techniques: the femoral neck system (FNS) and cannulated compression screws (CCSs).

A total of 40 female patients (mean age 73.50 ± 11.55 years) with femoral neck fractures of Pauwels classification type II and receiving surgical fixation between 2020 and 2022 were enrolled. The patients were categorized into an FNS group (n = 12) or a CCS group (n = 28), and surgical duration, intraoperative blood loss, length of hospital stay, and incidence of postoperative adverse events were analyzed.

No significant intergroup differences in demographic characteristics were discovered. The mean surgical duration for all patients was 52.88 ± 22.19 min, with no significant difference between the groups. However, the FNS group experienced significantly higher intraoperative blood loss (P = 0.002) and longer hospital stay (P = 0.023) than did the CCS group. The incidence of osteonecrosis was higher in the CCS group, whereas the incidence of nonunion or malunion was higher in the FNS group. The surgical method did not appear to be a significant risk factor. The main risk factor for revision surgery was longer duration until the first adverse event (P = 0.015).

The FNS does not appear to provide superior surgical outcomes compared with CCSs in older adult women with Pauwels classification type II femoral neck fractures. A longer duration between surgical fixation and the first adverse event before stabilization of the fracture site may be a risk factor for revision surgery.

To investigate the early effectiveness of the Ti-Robot assisted femoral neck system (FNS) in the treatment of elderly Garden type Ⅱ and Ⅲ femoral neck fractures.

A retrospective analysis was conducted on the clinical data of 41 elderly patients with Garden type Ⅱ and Ⅲ femoral neck fractures who were admitted between December 2019 and August 2022 and met the selection criteria. Among them, 21 cases were treated with Ti-Robot assisted FNS internal fixation (study group), and 20 cases were treated solely with FNS internal fixation (control group). There was no significant difference in baseline data, including gender, age, side, cause of injury, time from injury to surgery, fracture Garden classification, and fracture line classification, between the two groups ( P>0.05). Surgical effectiveness was evaluated based on parameters such as operation time (including incision time and total operation time), reduction level, number of dominant pin insertions, intraoperative fluoroscopy frequency, incision length, whether to extend the incision, need for assisted reduction, postoperative hospital stay, fracture healing time, incidence of osteonecrosis of the femoral head, postoperative visual analogue scale (VAS) score at 1 day, and Harris hip score at last follow-up.

The study group showed significantly shorter incision time, fewer dominant pin insertions, fewer instances of extended incisions, fewer intraoperative fluoroscopy frequency, and smaller incisions than the control group ( P<0.05). There was no significant difference in total operation time, reduction level, and assisted reduction frequency between the two groups ( P>0.05). Both groups achieved primary wound healing postoperatively, with no complications such as incision leakage or skin infection. All patients were followed up 12-24 months with an average of 14.6 months. Fractures healed in both groups, with no significant difference in healing time ( P>0.05). There was no significant difference in postoperative hospital stay between the two groups ( P>0.05). The study group showed significantly better VAS score at 1 day after operation and Harris hip score at last follow-up when compared to the control group ( P<0.05). No complication such as internal fixation failure, fracture displacement, or hip joint varus occurred in both groups during the follow-up. Osteonecrosis of the femoral head occurred in 1 patient of the control group, while no was observed in the study group, and the difference in the incidence of osteonecrosis of the femoral head between the two groups was not significant ( P=0.488).

Compared to sole FNS internal fixation treatment, Ti-Robot assisted FNS internal fixation for elderly Garden typeⅡ and Ⅲ femoral neck fractures can reduce incision time, achieve minimally invasive and accurate nail implantation, and decrease intraoperative fluoroscopy frequency, leading to improved postoperative hip joint function recovery.

Femoral neck system (FNS) is a new type of internal fixation system which has been widely used for treating femoral neck fractures (FNFs).Compared with other internal fixation methods, FNS is minimally invasive and stable, and often achieves satisfactory short-term efficacy.Early failure of FNS (EFFNS) is not uncommon, however, there are few literatures and reports on factors associated with EFFNS.This study aimed to survey the prevalence and risk factors of EFFNS.

We retrospectively analysed 62 patients with FNFs and underwent FNS fixation between 2019 and 2021. Demographic data, clinical characteristics, radiographic features and treatment process were described. Multifactor logistic regression analysis was used to analyse the different influencing factors.

Out of the 62 FNFs patients, 10 patients (16.1%) developed EFFNS, including 6 cases of severe femoral neck shortening, 2 cases of screw-out, 1 case of avascular necrosis of the femoral head and 1 case of nonunion. In the failure group, all patients were younger than 65 years old, which was significantly higher than 59.6% in the healing group (P = 0.012). There were no significant differences in sex(P = 0.490), BMI (P = 0.709), injured side (P = 0.312), injury mechanism (P = 0.617), reduction method(P = 0.570),femoral neck-shaft angle(P = 0.545), Pauwels classification (P = 0.564) and Garden classification (P = 0.195). Moreover, we not found that Garden classification (P = 0.464) and age (P = 0.128) were statistically significant risk factors for EFFNS at multivariate analysis.

In this study, sex, BMI, injury side, injury mechanism, reduction method, Pauwels angle, femoral neck-shift angle, Pauwels classification and Garden classification were excluded as EFFNS risk factors. Moreover, our study demonstrated that age and Garden classification were not significant risk factors at multivariate analysis.

ChiCTR, ChiCTR2100051360. Registered on 21 September, 2021. https://www.chictr.org.cn/index.aspx .

The accuracy of screw placement is a key factor for the stability of the cannulated screws used in the fixation of femoral neck fractures. In this study we designed a navigation device for ensuring the screw reaches the ideal position for optimal fixation. From March 2019 to September 2020, 66 patients with femoral neck fracture were enrolled and divided into 2 groups, one group was treated using the traditional free-hand cannulated screw fixation and the other using the new navigation device with assisted fixation. The effectiveness of the 2 methods was compared based on surgery duration, intraoperative bleeding, number of fluoroscopic examination and guidewire insertion attempts, screw parallelism, and effective fixation area. Fracture healing, complications and hip joint function were assessed after operation. The new navigation device reduced the duration of surgery without causing additional intraoperative bleeding, and significantly reduced number of fluoroscopy examination and guidewire insertion attempts (4.00±1.58 vs. 6.09±1.94 with traditional surgery). The accuracy of screw implantation was improved, as demonstrated by increased screw parallelism (0.71±0.57° vs. 1.66 ±1.01° with traditional surgery) and higher effective fixed area (64.88±10.52 vs. 58.61±9.19 mm2 with traditional surgery). In the postoperative follow-up, except for one case of femoral head necrosis and one case of bone nonunion in the traditional surgical group, the other patients showed fracture healing. There was no significant difference in hip joint function between the 2 groups. The new navigation device enables rapid and accurate guidewire positioning for cannulated screw fixation through simple operation procedures, resulting in good prospect for clinical transformation.

Femoral neck fractures (FNFs) affect the young adult population and are intimately related to high-energy trauma. Despite innovations in osteosynthesis materials, the rate of complications remains at 10%-59% in Pauwels type III (PIII) fractures. The authors thus propose a fixation model with a novel self-compression screw, comparing it to a sliding hip screw plate associated with a derotation screw in the fixation of a PIII fracture with posterior inferior comminution. The finite element method (FEM) was used in this comparison along with a virtual femur model with structural characteristics similar to those of a healthy young human bone. We formed 4 groups: Group 1 (GC), intact bone; Group 2 (SHS+S), sliding hip screw plate with derotation screw; Group 3 (XS), X-pin + SS (self-compression model with superior positioning screw); Group 4 (XI), X-pin + IS (self-compression model with inferior positioning screw). A 700 N monotonic load was applied to the apex of the femur head towards the ground so that stress was mainly focused on the fracture site and osteosynthesis. Analyses included total displacement and maximum principal stress and were performed for all groups. Fracture displacement, rotation, and von Mises were assessed only in groups that underwent osteosynthesis. Total displacement values in groups with self-compression screws (XS and XI) were closer to those for healthy femurs, with a 38.5% reduction when comparing the XS group with the SHS+S group. Fracture displacement and rotation values presented reductions of over 60% when comparing the XS and XI groups with the SHS+S group. Equivalent Von Mises stress values were similar between XS and XI and presented a reduction of approximately 5.25% when compared with the SHS+S group. Our FEM analyses demonstrated that the self-compression screw model has potential biomechanical advantages over the SHS+S model.

Most displaced femoral neck fractures can achieve satisfactory anatomical reduction by closed reduction, but there are still some that cannot reset satisfactorily after closed reduction, and open reduction are required. Such fractures that cannot be repositioned successfully by closed reduction are called irreducible displaced femoral neck fractures in this study. The objective of our study was to evaluate the efficacy of direct anterior incision with the Femoral Neck System in the treatment of irreducible displaced femoral fractures.

A total of 16 young and middle-aged patients with irreducible displaced femoral neck fractures involving Garden type III and IV were treated using Femoral Neck System fixation by open reduction through Direct Anterior Approach between January 2020 to September 2021. Functional outcomes and postoperative complications were assessed during follow-up. Clinical outcomes were evaluated by the Hip Harris score. The postoperative reduction was evaluated by the Garden Index. Observe postoperative complications.

All patients were followed up with a mean follow-up time of 21.1(12-30) months, and according to radiological results, all patients achieved fracture healing, with a mean healing time of 4.25 months. All 16 patients received grade Garden I and II reductions, and there was no significant difference in the anteroposterior Garden reduction index between the first day after surgery (166.13 ± 5.61) and the 12th month after surgery(164.94 ± 4.49) (P>0.05) and no significant difference in lateral Garden index between the first day after surgery(171.06 ± 4.46) and the 12th month after surgery(169.38 ± 3.98) (P<0.05). According to the Hip Harris score scale, 13 patients received excellent and 3 patients received good. The postoperative Hip Harris Score(17.19 ± 4.8) was significantly higher than the preoperative score(92.19 ± 3.4), and the difference was statistically significant (P < 0.05). No or mild femoral neck shortness occurred in 12 (75%) patients, moderate shortening occurred in 3 (18.75%) patients, and severe shortening occurred in 1 (6.25%) patient. None of the patients experienced femoral head necrosis, fracture nonunion, or incision infection. One patient developed deep venous thrombosis of the lower extremity.

The Direct Anterior Approach combined with Femoral Neck System is an excellent treatment for irreducible displaced femoral neck fracture and achieved good functional outcomes and anatomical reduction with low complications.

The femoral neck system (FNS) was introduced as a minimally invasive fixation device for managing femoral neck fractures.

To compare radiographic, clinical, and patient-reported outcome measures (PROMs) of femoral neck fracture patients following FNS compared to dynamic hip screw (DHS) implantation combined with an anti-rotational screw.

Patients who underwent closed reduction and internal fixation of a femoral neck fracture between 2020 and 2022 were retrospectively included. We measured leg length, femoral offset, and centrum-collum-diaphyseal (CCD) angle in plain radiographs. Scar length, Harris Hip Score, short-form health survey 36-item score (SF-36), and Numeric Rating Scale (NRS) were assessed during follow-up visits.

We included 43 patients (22 females) with a median age of 66 (IQR 57, 75). In both groups, leg length differences between the injured and the contralateral side increased, and femoral offset and CCD angle differences were maintained over time. FNS patients had shorter scars and reported fewer emotional problems and more energy. There were no differences between groups regarding the remaining SF-36 sub-scores, Harris Hip Score, and NRS.

The FNS allows for a comparable leg length, femoral offset, and CCD angle reconstruction while achieving similarly high functional and global health scores to the DHS.

The aim of the present study was to investigate the clinical efficacy of three cannulated screws with parallel distribution in comparison with the 'gold standard' of inverting three cannulated screws with triangular distribution, in the treatment of femoral neck fractures in the elderly. A total of 106 elderly patients with femoral neck fractures treated at the Department of Orthopedics of the First Affiliated Hospital of Nanjing Medical University (Jiangsu Provincial Hospital) from October 2018 to March 2020 were retrospectively analyzed and divided into groups A and B. Group A consisted of 51 patients with a mean age of 73.3±6.8 years; and group B consisted of 55 patients with a mean age of 74.5±7.3 years. Group A was treated with closed reduction + inverted triangular distribution of three cannulated screws, while group B was treated with closed reduction + parallel distribution of three cannulated screws, and the general surgical conditions, including fracture reduction quality, fracture healing, incidence of avascular necrosis of the femoral head, and functional recovery scale (FRS) score of hip joint function were assessed in both groups. All patients were followed up for an average of 14.8 months. Compared with group A, group B had significant advantages in operation time, number of times intraoperative fluoroscopy was performed, number of intraoperative guide wire adjustments, and proportion of postoperative referrals to the intensive care unit (P<0.05). There were no significant differences in fracture reduction quality, fracture healing, incidence of avascular necrosis of the femoral head, and FRS score of hip joint function between groups A and B (P>0.05). For elderly patients with femoral neck fractures, distributing three cannulated screws in parallel after closed reduction achieved similar clinical efficacy to 'gold standard' inverted triangular distribution, and had obvious advantages in operation time, with significantly reduced surgical difficulty. This procedure is therefore deemed worthy of promotion and clinical application in the primary hospitals of China.

Internal fixation of the femoral neck carries a risk of perforation due to the presence of the isthmus of the femoral neck. At present, there are few studies on the safe and risk zones of the femoral neck system (FNS) implantation. This study aimed to recommend the safe range of injection of FNS in the lateral wall of the proximal femur, parallel to the axis of the femoral neck, during FNS treatment of femoral neck fracture (FNF).

Femoral computed tomography (CT) data of 80 patients (male: 40; female: 40) who met the inclusion criteria were collected. Mimics 21.0 software was used to complete the modeling. 3-Matic 13.0 software was used to establish the axis of the femoral neck and its vertical plane, perform the cutting of the femoral neck, and project it on the vertical plane of the femoral neck axis. After matching a rectangle for each projection map, all sample sizes (80 cases) were standardized and superimposed to obtain gradient maps of the safe zone (SZ) and dangerous zone (RZ), thereby securing edge key points and safe FNS insertion range.

In the 80 samples, the mean diameter of the smallest femoral neck section was 33.87 ± 2.32 mm for men and 29.36 ± 1.92 mm for women. All 80 femoral necks had safe and risky areas. The SZ/S × 100% was 77.59 (± 2.22%), and the RS/S × 100% was 22.39% (± 2.22%). The risk area was composed of four parts: (1), (2), (3), and (4), respectively, corresponding to 3.45 ± 1.74%, 5.51 ± 2.63%, 6.22 ± 1.41%, and 7.22 ± 1.39%. Four marginal key points, perforation risk, and safe ranges (SR) of FNS were analyzed on the lateral wall of the femoral neck.

The SR of FNS placement was recommended by digital simulation. In addition, Regions (3) and (4) posed a higher risk of penetrating the cortex. Using the gradient map of RZ for preoperative evaluation is recommended to avoid iatrogenic perforation.

High shear force is a major factor detrimental to the healing of vertical femoral neck fractures. In addition to firm fixation, reduction quality is crucial for postoperative stability. The present study aimed to compare the biomechanical stability of the newly invented femoral neck system and three inverted-triangle cannulated compression screws treatments for non-anatomical reduction of Pauwels type-III femoral neck fractures.

A total of 18 non-anatomical reduction Pauwels type-III femoral neck fracture finite element models were fabricated and fixed using three inverted-triangle cannulated compression screws or the femoral neck system. A 1950-N force was applied to the femoral head to simulate the physiological load during a single-leg stance. Parameters of the maximum total deformation, the interfragmentary gap, and the maximum von Mises stress of the implants and the proximal femur were analyzed.

The results of the maximum total deformation, interfragmentary gap, and maximum von Mises stress of the implants in the negative-negative buttress model fixed by the femoral neck system were the largest among all groups (3.58 mm, 0.252 mm, and 729.68 MPa, respectively). In contrast, the anatomical-anatomical reduction model fixed by three inverted-triangle cannulated compression screws demonstrated the minimum total deformation, interfragmentary gap, and minimum von Mises stress of implants (1.107 mm, 0.09 mm, and 189.83 MPa, respectively).

Anatomical reduction or positive buttress in femoral neck fractures should be recommended during fracture reduction. The femoral neck system showed weaker biomechanical stability than three inverted-triangle cannulated compression screws in treating Pauwels type-III femoral neck fractures.

This meta-analysis aimed to compare the relative safety and efficacy of cannulated compression screw (CCS) and femoral neck system (FNS) in treating patients with femoral neck fractures and to provide evidence-based medical evidence for FNS in treating femoral neck fractures.

PubMed, Embase, Cochrane, and China National Knowledge Infrastructure databases were searched to collect outcomes related to femoral neck fractures treated with FNS and CCS, including time to fracture healing, incidence of non-union, incidence of osteonecrosis of the femoral head, incidence of failure of internal fixation, rate of femoral neck shortening, Harris hip score, Barthel index, operative time, intraoperative blood loss, fluoroscopy frequency, and complications. A meta-analysis was performed using RevManv5.4 (The Cochrane Collaboration) and Stata v14.0 software.

This analysis included 21 studies involving 1,347 patients. The results showed that FNS was superior to CCS in terms of fracture healing time [mean difference (MD) = -0.75, 95% CI = (-1.04, -0.46), P < 0.05], incidence of bone non-union [odds ratio (OR) = 0.53, 95% CI = (0.29, 0.98), P = 0.04], incidence of osteonecrosis of the femoral head [OR = 0.49, 95% CI = (0.28, 0.86), P = 0.01], incidence of internal fixation failure [OR = 0.30, 95% CI = (0.18, 0.52), P < 0.05], rate of femoral neck shortening [OR = 0.38, 95% CI = (0.27, 0.54), P > 0.05], Harris hip score [MD = 3.31, 95% CI = (1.99, 4.63), P < 0.001], Barthel index [MD =  4.31, 95% CI = (3.02, 5.61), P < 0.05], intraoperative bleeding [MD = 14.72, 95% CI = (8.52, 20.92), P < 0.05], fluoroscopy frequency [OR = 0.53, 95% CI = (0.29, 0.98), P = 0.04], and complications [OR = 0.31, 95% CI = (0.22, 0.45), P < 0.05]. The difference between FNS and CCS in operative time was not statistically significant [MD = -2.41, 95% CI = (-6.88, 2.05), P = 0.29].

FNS treatment of femoral neck fracture can shorten the fracture healing time; reduce the incidence and translucent rate of bone non-union, osteonecrosis of the femoral head, and internal fixation failure; reduce intraoperative blood loss and postoperative complications; and improve hip joint function and activity. We are confident in the findings that FNS, an effective and safe procedure for internal fixation of femoral neck fractures, is superior to CCS.

Hip fractures in the elderly population are common and the number of patients is rising. For young and geriatric patients with undisplaced fractures osteosynthesis is the primary type of treatment. The dynamic hip screw (DHS) is around for many years and proved its value especially in displaced fractures. Since 2018 the femoral neck system (FNS) is available as an alternative showing promising biomechanical results. The aim of this study is to evaluate clinical results of the FNS and compare it to the DHS.

Patients older than 18 years with Garden I-IV fractures that were treated with osteosynthesis in a level 1 trauma center were included in the study. Between January 2015 and March 2021, all patients treated with FNS (1-hole plate, DePuy-Synthes, Zuchwil, Switzerland) or DHS (2-hole plate, DePuy-Synthes, Zuchwil, Switzerland) for proximal femur fractures were included in the study. Closed reduction was achieved using a traction table. All operations were carried out by experienced orthopedic trauma surgeons. Primary outcome measures were rate of implant failure (cut out) and surgical complications (hematoma, infection). Secondary outcome measures were Hb-difference, length of hospital stay and mortality.

Overall, 221 patients were included in the study. 113 were treated with FNS, 108 with DHS. Mean age was 69 ± 14 years. There were 17.2% Garden I, 47.5% Garden II, 26.7% Garden III and 8.6% Garden IV fractures. No difference between the groups for age, body mass index (BMI), Charlson comorbidity index (CCI), time to surgery, Pauwels and Garden classification, rate of optimal blade position or tip apex distance was found. FNS showed lower pre- to postoperative Hb-difference (1.4 ± 1.1 g/l vs. 2.1 ± 1.4 g/l; p < 0.05), shorter operating time (36.3 ± 11.6 min vs. 54.7 ± 17.4 min; p < 0.05) and hospital stay (8.8 ± 4.3 d vs. 11.2 ± 6.8 d; p < 0.05). Surgical complications (FNS 13.3% vs. DHS 18.4%, p > 0.05), rate of cut out (FNS 12.4% vs. DHS 10.2%, p > 0.05) and mortality (FNS 3.5%; DHS 0.9%; p > 0.05) showed no difference between the groups. Logistic regression showed that poor blade position was the only significant predictor for cut out and increased the risk by factor 7. Implant related infection (n = 3) and hematoma/seroma (n = 6) that needed revision was only seen in DHS group.

FNS proved to be as reliable as DHS in all patients with hip fractures. Not the type of implant but blade positioning is still key to prevent implant failure. Still due to minimal invasive approach implant related infections and postoperative hematomas might have been prevented using the FNS.

To investigate the effects of postoperative femoral neck shortening in patients with femoral neck fractures fixed with femoral neck system screws (FNS) and to explore the factors influencing femoral neck shortening.

To retrospectively analyze the data of 113 patients with femoral neck fractures admitted to the Second Hospital of Fuzhou City, affiliated with Xiamen University, between December 2019 and January 2022. Of these, 87 patients were followed up for more than 12 months, 49 men and 38 women: 36 cases of Garden I and II fractures and 51 cases of Garden III and IV fractures, to record the patient's hip Harris score at 12 months postoperatively. Patients were divided into femoral neck shortening group and femoral neck no shortening group according to their regular postoperative follow-up radiographic measurements. To count the incidence of femoral neck shortening, a comparison of postoperative complication rates and hip Harris scores between the two groups was made. Statistical comparison of the two groups and a multifactorial logistic regression analysis were also performed to analyze the factors affecting femoral neck shortening.

All 87 patients were followed up for more than 12 months after surgery. In 34 of these cases, neck shortening occurred, and the incidence rate was 39.1%. 15 cases of severe shortening, incidence of 17.2%; fracture healing 84 cases, fracture healing rate of 96.5%. The hip Harris score was 83.99 (81.95, 89.20) in the neck shortening group at 12 months postoperatively, 90.87 (87.95, 94.80) for the group without neck shortening; the difference between the two groups was statistically significant (P < 0.01). 32 cases of fracture healing in the neck shortening group at 12 months after surgery, fracture healing rate of 94.1%; 52 cases healed without neck shortening group, fracture healing rate of 98.1%. The difference between the two groups was not statistically significant (P = 0.337). High incidence of neck shortening after FNS fixation of femoral neck fractures, cortical comminution of the severed end, fracture fractionation and quality of reduction were significantly correlated with neck shortening.

High incidence of postoperative neck shortening after internal fixation of femoral neck fractures with the femoral neck system, the cortical comminution, the type of fracture, and the quality of fracture reduction are the influencing factors; femoral neck shortening can affect postoperative hip function, but does not affect fracture healing.