A Comparative Analysis of Femoral Neck System and Three Cannulated Screws Fixation in the Treatment of Femoral Neck Fractures: A Six-Month Follow-Up

Femoral Neck System Compared with 3 Cannulated Screws in the Treatment of Femoral Neck Fracture in Patients Aged 60 and Older: A Multicenter Registry-Based Study

BACKGROUND

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.

METHODS

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.

RESULTS

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).

CONCLUSIONS

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.

LEVEL OF EVIDENCE

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

Biomechanical Stability of Femoral Neck System for Pauwels Type III Femoral Neck Fractures Based on Different Reduction Quality

To further investigate the biomechanics of a femoral neck system (FNS) for Pauwels type III femoral fractures based on three different reductions.We constructed three different reduction (anatomical reduction, negative buttress reduction, and positive buttress reduction) models of Pauwels type III femoral neck fractures. Then, three cannulated screws (3CS), dynamic hip screws (DHS), dynamic hip screws combined with an anti-rotation screw (DHS + ARS), one-hole femoral neck system (1HFNS), and two-hole femoral neck system (2HFNS) were assembled with the reduction models, respectively, to simulate the internal fixation surgical procedure. All models had a load of 2100 N in line with the femoral mechanical axis applied. The implant stress, the head and implant displacements, and the rotational angles of all models were recorded and analyzed.Compared to 3CS and 2HFNS, 1HFNS had higher implant stress (higher than 92.5 MPa and 46.3 MPa, respectively) and displacement (higher than 0.9 mm and 0.8 mm, respectively) in the anatomical reduction. 2HFNS exhibited the highest stress values (225.5 MPa) in the anatomical reduction but the lowest values (159.8 MPa) in the positive buttress reduction when compared to the other implants. 2HFNS showed the best rotational stability in the negative and positive buttress reduction (rotational angels of 0.8° and 0.6°, respectively).Based on the outcome of this computational study, it might be concluded that 2HFNS was an alternative fixation for the treatment of Pauwels type III femoral neck fracture, especially when anatomical reduction cannot be perfectly attained. More relevant clinical and biomechanical studies are needed in the future.

Treatment of a femoral neck fracture in a patient with dwarfism: a case report

BACKGROUND

Femoral neck fractures in patients with pituitary dwarfism present significant surgical challenges due to anatomical variations, compromised bone quality, and limited therapeutic options. The management of such cases requires careful consideration of both the anatomical constraints of and the potential complications associated with various fixation methods.

CASE PRESENTATION

This report presents the case of a 30-year-old female with congenital pituitary dwarfism who sustained a subcapital femoral neck fracture following trauma. After suffering a workplace injury due to a fall, the patient experienced left hip pain, limited mobility, and difficulty walking. The patient presented with characteristic features of dwarfism, including diminutive stature (1.2 m), multiple skeletal abnormalities, and significant osteoporosis. X-ray and hierarchical phase-contrast tomography examinations of the left hip joint revealed a displaced subcapital femoral neck fracture with compromised bone quality and a notably narrow medullary cavity. Surgical treatment was subsequently performed on the patient. After the onset of combined spinal-epidural anesthesia, the patient was placed on a traction bed and closed reduction was attempted three times, all unsuccessfully. The direct anterior approach in the supine position was then chosen for open reduction of the left subcapital femoral neck fracture. After surgery, pain relief and treatment to prevent venous thrombosis were provided. A postoperative digital radiography examination of the left hip showed good alignment of the fracture fragments. Two weeks post-surgery, the stitches were removed and the patient was discharged.

CONCLUSIONS

This study aimed to fill the gap in the literature on the selection of internal fixation methods for femoral neck fractures in patients with pituitary dwarfism. Compared with the widespread use of three cannulated screws, the femoral neck system (FNS), a type of internal fixation device for treating femoral neck fractures, was chosen for internal fixation within the medullary cavity due to stenosis. This method avoided the need for multiple drillings with guide pins to ensure internal fixation. Although the procedure prolonged the surgery, it provided better stability and compression capability at the fracture site. The outcome showed that the FNS was a better choice for patients with a similar condition.

Femoral neck system (FNS) versus 4 cannulated compression screws (CCSs) in the treatment of young patients with Pauwels type III femoral neck fracture: a retrospective comparative study

OBJECTIVE

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.

METHODS

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.

RESULTS

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).

CONCLUSION

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.

Fracture classification and coronal plane position of bolt may affect the prognosis after femoral neck system (FNS) surgery for femoral neck fractures

PURPOSE

This study aims to investigate the risk factors for postoperative complications following Femoral Neck System (FNS) fixation in young patients with femoral neck fractures (FNFs).

METHODS

We retrospective analyzed 133 patients with FNFs who underwent FNS fixation between May 2021 and October 2023. Potential risk factors that may affect the results included age, gender, body mass index (BMI), Pauwels classification, Garden classification, fracture anatomical classification, reduction method, reduction quality, coronal plane position of the FNS bolt. Postoperative complication data, including femoral head necrosis, nonunion, shortening of the femoral neck, fracture displacement, and screw cut-out, were collected. Multivariate logistic regression analysis was used to analyze different influencing factors.

RESULTS

A total of 133 FNFs patients were divided into a healing group (108 patients) and a failure group (25 patients). 25 patients (18.79%) had postoperative complications, including 8 cases of femoral head necrosis, 3 cases of nonunion, 3 cases of significant shortening of the femoral neck, and 7 cases of fracture displacement, 4 cases of screw cut-out; the remaining patients' fractures all healed. There were no statistical differences between the two groups in age (P = 0.746), gender (P = 0.992), BMI (P = 0.361), Pauwels classification (P = 0.231), fracture anatomical classification (P = 0.459), reduction method (P = 0.383). Garden classification significantly influenced postoperative complications, with the proportion of Garden type IV being significantly higher in the failure group than in the healing group (64% vs. 39.8%, P = 0.01). Multivariate logistic regression analysis showed that coronal position of the FNS bolt and reduction quality were risk factors for postoperative complications. Subgroup analysis using logistic regression showed a positive correlation between coronal plane position of the FNS bolt and reduction quality with the occurrence of postoperative complications, with FNS positioned in the upper 1/3 and negative support being significant risk factors (P < 0.01; P < 0.01).

CONCLUSIONS

FNS is an effective method for treating FNFs in young adults, but there is still a certain risk of failure. The Garden classification is an important evaluation indicator for postoperative complications, with a higher failure rate observed in type IV fractures. Coronal plane position of the FNS bolt and reduction quality are significant risk factors for failure after FNS surgery for FNFs.

Evaluation of Post-Operative Outcomes of Femoral Neck Fracture Interventions: A Systematic Review

Introduction

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.

Significance

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.

Results

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.

Conclusion

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.

Efficacy of four internal fixation devices on femoral neck fractures in young adults: A systematic review and network meta-analysis

BACKGROUND

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.

METHODS

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.

RESULTS

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).

CONCLUSION

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.

Fixation of adult femoral neck fractures: Retrospective comparison between cannulated screws and femoral neck system (FNS)

OBJECTIVE

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.

METHOD

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.

RESULTS

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.

CONCLUSIONS

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.

Surgical treatment of non-displaced subcapital hip fracture: Femoral Neck System vs. cannulated screws. Comparative study

OBJECTIVE

The objective of this study is to compare the outcomes of using the Femoral Neck System (FNS) (DePuy Synthes®) versus the use of cannulated screws (CS) in the surgical treatment of non-displaced subcapital hip fractures.

MATERIALS AND METHODS

A retrospective cohort study was conducted on non-displaced subcapital hip fractures treated with CS or FNS between 2020 and 2023, with a minimum follow-up of one year. A total of 28 patients were included, 14 treated with CS and 14 with FNS. Demographic, radiological, clinical, and functional variables were analyzed.

RESULTS

In the CS group, 64% were male, with a mean age of 66.5 years (SD 14.9) and an average follow-up of 22 months (range, 12-36 months). In the FNS group, 57% were male, with a median age of 60.8 years (SD 13.78) and an average follow-up of 16 months (range, 12-24 months). Regarding functional outcomes, no significant differences were found between FNS and CS in the Harris scale: 94.21±11.55 for FNS and 96.50±6.9 for CS (p=0.618). The total postoperative complications (FNS/CS) were 7.1% versus 43%, and implant failure with conversion to total hip replacement was 0% versus 43%, both significantly higher in the CS group (p=0.047; p=0.016, respectively). The FNS also presented a lower rate of avascular necrosis (0% versus 11.1%, p=0.391) and nonunion (0% versus 20%, p=0.163), although these differences did not reach statistical significance.

CONCLUSIONS

Although both treatment methods, cannulated screws and the FNS, showed similar short-term functional outcomes in the management of undisplaced subcapital femoral fractures, the FNS demonstrated a significantly lower rate of complications and reoperations. These results suggest that the FNS could be considered a safer and more effective option compared to cannulated screws.

Evaluating three internal fixation techniques for Pauwels III femoral neck fractures via finite element analysis

The selection of implants for fixing unstable femoral neck fractures (FNF) remains contentious. This study employs finite element analysis to examine the biomechanics of treating Pauwels type III femoral neck fractures using cannulated compression screws (3CS), biplane double-supported screw fixation (BDSF), and the femoral neck system (FNS). A three-dimensional model of the proximal femur was developed using computed tomography scans. Fracture models of the femoral neck were created with 3CS, BDSF, and FNS fixations. Von Mises stress on the proximal femur, fracture ends, internal fixators, and model displacements were assessed and compared across the three fixation methods (3CS, BDSF, and FNS) during the heel strike of normal walking. The maximum Von Mises stress in the proximal fragment was significantly higher with 3CS fixation compared to BDSF and FNS fixations (120.45 MPa vs. 82.44 MPa and 84.54 MPa, respectively). Regarding Von Mises stress distribution at the fracture ends, the highest stress in the 3CS group was 57.32 MPa, while BDSF and FNS groups showed 51.39 MPa and 49.23 MPa, respectively. Concerning implant stress, the FNS model exhibited greater Von Mises stress compared to the 3CS and BDSF models (236.67 MPa vs. 134.86 MPa and 140.69 MPa, respectively). Moreover, BDSF displayed slightly lower total displacement than 3CS fixation (7.19 mm vs. 7.66 mm), but slightly higher displacement than FNS (7.19 mm vs. 7.03 mm). This study concludes that BDSF outperforms 3CS fixation in terms of biomechanical efficacy and demonstrates similar performance to the FNS approach. As a result, BDSF stands as a dependable alternative for treating Pauwels type III femoral neck fractures.

Finite Element Analysis of Six Internal Fixations in the Treatment of Pauwels Type III Femoral Neck Fracture

OBJECTIVE

The current investigation sought to utilize finite element analysis to replicate the biomechanical effects of different fixation methods, with the objective of establishing a theoretical framework for the optimal choice of modalities in managing Pauwels type III femoral neck fractures.

METHODS

The Pauwels type III fracture configuration, characterized by angles of 70°, was simulated in conjunction with six distinct internal fixation methods, including cannulated compression screw (CCS), dynamic hip screw (DHS), DHS with de-rotational screw (DS), CCS with medial buttress plate (MBP), proximal femoral nail anti-rotation (PFNA), and femoral neck system (FNS). These models were developed and refined using Geomagic and SolidWorks software. Subsequently, finite element analysis was conducted utilizing Ansys software, incorporating axial loading, torsional loading, yield loading and cyclic loading.

RESULTS

Under axial loading conditions, the peak stress values for internal fixation and the femur were found to be highest for CCS (454.4; 215.4 MPa) and CCS + MBP (797.2; 284.2 MPa), respectively. The corresponding maximum and minimum displacements for internal fixation were recorded as 6.65 mm for CCS and 6.44 mm for CCS + MBP. When subjected to torsional loading, the peak stress values for internal fixation were highest for CCS + MBP (153.6 MPa) and DHS + DS (72.8 MPa), while for the femur, the maximum and minimum peak stress values were observed for CCS + MBP (119.3 MPa) and FNS (17.6 MPa), respectively. Furthermore, the maximum and minimum displacements for internal fixation were measured as 0.249 mm for CCS + MBP and 0.205 mm for PFNA. Additionally, all six internal fixation models showed excellent performance in terms of yield load and fatigue life.

CONCLUSION

CCS + MBP had the best initial mechanical stability in treatment for Pauwels type III fracture. However, the MBP was found to be more susceptible to shear stress, potentially increasing the risk of plate breakage. Furthermore, the DHS + DS exhibited superior biomechanical stability compared to CCS, DHS, and PFNA, thereby offering a more conducive environment for fracture healing. Additionally, it appeared that FNS represented a promising treatment strategy, warranting further validation in future studies.

Bio-mechanical effects of femoral neck system versus cannulated screws on treating young patients with Pauwels type III femoral neck fractures: a finite element analysis

INTRODUCTION

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.

METHODS

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.

RESULTS

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.

CONCLUSIONS

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.

Comparison of percutaneous compression plate to parallel screws in the treatment of nondisplaced femoral neck fractures in elderly patients: a prospective, randomized study

BACKGROUND

The optimal internal fixation for non-displaced femoral neck fractures remains controversial. This study aimed to compare the clinical results of the percutaneous compression plate (PCCP) with parallel screws (PS) in treating femoral neck fractures in elderly patients.

MATERIALS AND METHODS

A total of 218 patients who underwent internal fixation were randomized to receive either a percutaneous compression plate (PCCP group) or parallel screws (PS group) using a computerized random sequence generator which was used to assign the order of randomization. Patients were assessed by the operating time, intraoperative blood loss, hemoglobin level drop, postoperative hospital stay, the time to full weight-bearing, reduction quality, fracture healing time, Harris hip score, and postoperative complications.

RESULTS

There was no significant difference between PCCP and PS groups regarding operative time, intraoperative blood loss, hemoglobin level drop, postoperative hospital stays, reduction quality, and Harris hip score (p > 0.05). The time to full weight-bearing and the fracture healing time in the PCCP group were shorter than those in the PS group (p < 0.05). The overall complication rates were slightly lower in the PCCP compared to the PS patients, but there was no significant difference (p > 0.05). However, the implant failure rate was significantly higher in the PS group compared to the PCCP group (p < 0.05).

CONCLUSIONS

The present study suggests that the PCCP is superior to the parallel screws fixation in the treatment of non-displaced elderly femoral neck fractures in terms of earlier full weight-bearing, shorter fracture healing time, and lower implant failure rate. Therefore, it may be a better therapeutic strategy for non-displaced femoral neck fractures in elderly patients.

Restoration of Hip Geometry after Femoral Neck Fracture: A Comparison of the Femoral Neck System (FNS) and the Dynamic Hip Screw (DHS)

BACKGROUND

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

OBJECTIVE

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.

METHODS

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.

RESULTS

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.

CONCLUSIONS

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.

Prediction of hip joint function and analysis of risk factors for internal fixation failure after Femoral Neck System (FNS)

OBJECTIVE

Analysis of the risk factors affecting hip function and complications after femoral neck system (FNS) surgery for femoral neck fractures is of great significance for improving the procedure's efficacy.

METHODS

The data of patients with femoral neck fractures who underwent FNS surgery in our hospital between October 2019 and October 2020 were retrospectively analyzed. Age, gender, time from injury to operation, fracture classification, operation time, fracture reduction, and postoperative weight-bearing time information were set as potential factors that may affect the results. Hip Harris scores were performed at 12 months postoperatively, and postoperative complication data (e.g., femoral head necrosis, nonunion, and femoral neck shortness) were collected. The risk factors affecting hip function and complications after FNS surgery were predicted using linear and logistic regression analyses.

RESULTS

A total of 69 cases of femoral neck fracture were included, with an average age of 56.09 ± 11.50 years. The linear analysis demonstrated that the age and fracture type of the patients were the risk factors affecting the Harris score of the hip joint after FNS surgery. Older patients with displaced femoral neck fractures had an inferior postoperative hip function. In addition, fracture type, reduction of the femoral neck, and postoperative weight-bearing significantly impacted postoperative complications. Displaced fractures, negative fixation, and premature weight-bearing (< 6 weeks) were risk factors for postoperative complications. The Harris score of patients with a shortened femoral neck in the included cases was not significantly different from that of patients without shortening (P = 0.25).

CONCLUSIONS

Advanced age and fracture type are important evaluation indicators of the Harris score after FNS internal fixation of femoral neck fractures in young patients. Fracture type, fracture reduction, and postoperative weight-bearing time are risk factors for complications after FNS.

Femoral neck system vs. cannulated screws on treating femoral neck fracture: a meta-analysis and system review

Objective

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.

Methods

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.

Results

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].

Conclusion

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.

Nonanatomical reduction of femoral neck fractures in young patients treated with femoral neck system: a retrospective cohort study

PURPOSE

Negative buttress reduction should be avoided in the treatment of femoral neck fractures (FNFs) using conventional fixation. As the femoral neck system (FNS) has been recently developed and utilized widely to treat FNFs, the association of reduction quality with postoperative complications and clinical function has not been clarified. The purpose of this study was to evaluate the clinical effect of nonanatomical reduction in young patients with FNFs treated with FNS.

METHODS

This multicenter, retrospective cohort study included 58 patients with FNFs treated with FNS between September 2019 and December 2021. According to the reduction quality immediately following surgery, patients were classified into positive, anatomical, and negative buttress reduction groups. Postoperative complications were assessed with 12 months of follow-up. The logistic regression model was used to identify risk factors for postoperative complications. The postoperative hip function was assessed using the Harris hip scores (HHS) system.

RESULTS

At a follow-up of 12 months, a total of eight patients (8/58, 13.8%) had postoperative complications in three groups. Compared with the anatomical reduction group, negative buttress reduction was significantly associated with a higher complication rate (OR = 2.99, 95%CI 1.10-8.10, P = 0.03). No significant associations were found between positive buttress reduction and the incidence of postoperative complications (OR = 1.21, 95%CI 0.35-4.14, P = 0.76). The difference was not statistically significant in Harris hip scores.

CONCLUSION

Negative buttress reduction should be avoided in young patients with FNFs treated with FNS.

Comparison of femoral neck system and three cannulated cancellous screws in the treatment of vertical femoral neck fractures: clinical observation and finite element analysis

OBJECTIVE

The purpose of this study was to compare the biomechanical and clinical results of two surgical methods for the treatment of vertical femoral neck fractures: Femoral neck system (FNS) and traditional three cannulated cancellous screws (CCS).

METHODS

First, we developed three different vertical femoral neck fracture models for the finite element analysis, with angles of 55°, 65°, and 75°, respectively. Two experimental groups were set up: the FNS group and the CCS group. Each fracture group was tested under axial loads of 2100 N to measure the femur's displacement, Von Mises stress (VMS), and its internal fixation components. Secondly, we retrospectively included the cases of vertical femoral neck fractures with FNS and CCS in our hospital from May 2019 to May 2021. In this study, we compared the duration of intraoperative fluoroscopy, operative time, hospital stay, fracture healing time, Hemoglobin loss, Harris score of hip joint function, and postoperative complications among patients undergoing hip joint replacement.

RESULTS

In terms of finite element analysis, FNS has better anti-displacement stability than CCS at 55°and 65°, while FNS is greater than CCS in Von Mises stress. Clinically, we followed up on 87 patients for an average of 12 months. FNS was superior to traditional CCS in fracture healing time, operation time, fluoroscopy duration, fracture healing time, and Harris hip function score.

CONCLUSION

FNS is superior to traditional CCS in biomechanical and clinical aspects of treating vertical femoral neck fractures. There is potential for FNS to become a new treatment option for vertical femoral neck fractures.

Survivability of the Femoral Neck System for the treatment of femoral neck fractures in adults

INTRODUCTION

Hip fractures are common injuries in the elderly, with an incidence that continues to rise. The femoral neck system (FNS) recently emerged as a novel treatment option for femoral neck fractures, but long-term survivability of the implant remains uncertain. The purpose of this study is to evaluate survivability of the FNS and assess risk factors for implant failure.

METHODS

One hundred five adult patients who received the FNS (DePuy Synthes, Raynham, MA) for femoral neck fractures (AO/OTA 31B) were included. Surgeries were performed within a regional hospital system comprising 18 facilities. All patients had a minimum follow-up of 1 year. The primary outcome measures were cumulative incidence of implant failure and 1-year mortality, including risk factor analysis.

RESULTS

Twelve implants failed at a follow-up ranging from 17 days to 8 months, and 7 failed within 90 days. Cumulative incidence of implant failure was 2% at 30 days, 7% at 90 days, 12% at 6 months, and 13% at 1 year. Causes of implant failure included cut-out (n = 5), non-union (n = 4), peri-implant fracture (n = 2), and avascular necrosis (n = 1). Univariate Cox regression identified Pauwels type III fractures and an increasing AP Parker ratio as significant risk factors for failure. Pauwels type III fractures showed a 5.48 times higher risk compared to Pauwels types I & II. Every 10% increase in AP Parker ratio increased risk of failure by 2.39 times. The 1-year mortality rate was 21%, and univariate logistic regression identified age as the only risk factor (odds ratio = 3.71).

CONCLUSIONS

The incidence of implant failure and 1-year mortality rate in this study suggests that the FNS can provide reliable fixation compared to rates in the literature, but complications are not uncommon. Avoiding Pauwels type III fractures and optimizing implant placement appear crucial to preventing implant failure.

LEVEL OF EVIDENCE

Therapeutic Level IV.

Finite element comparative analysis of three different internal fixation methods in the treatment of Pauwels type III femoral neck fractures

BACKGROUND

Comparison of 4 cannulated lag screws (3 inverted triangular cannulated screws + anti-rotating screws;4 CLS), dynamic hip screws + derotational screws (DHS + DS), and femoral neck fixation system (FNS) in the treatment of Biomechanical properties of middle-aged Pauwels type III femoral neck fractures.

METHODS

The femur CT data of a healthy young volunteer was selected and imported into Mimics software to construct a three-dimensional model of a normal femur. Pauwels type III femoral neck fractures were simulated according to the 70° fracture line. Use Geomagic and SolidWorks software to optimize and build CLS, DHS + DS, and FNS fracture internal fixation models. Finally, Ansys software was used to analyze the stress distribution, peak value, and maximum displacement of the proximal fracture fragment and internal fixation; the displacement distribution, and peak value of the fracture surface at the fracture end.

RESULTS

① The stress peaks of the proximal fracture fragments in the three groups were concentrated near the femoral calcar. The peak stress of the FNS group was the largest, and the DHS + DS group was the smallest. ②The displacement of the fracture fragments was all located at the top of the femur. The peak displacement of the FNS group was the largest, and the DHS + DS group was the smallest. ③ The internal fixation stress of the three groups is concentrated in the middle part of the device. The stress distribution of the first two groups of models is more uniform than that of FNS. The peak stress of FNS is the largest and the CLS is the smallest. ④ The internal fixed displacements are all located at the top of the model. The peak displacement of the CLS is the largest, and the DHS + DS is the smallest. ⑤ The displacement of the fracture surface is in the upper part of the fractured end. The peak displacement of the FNS group was the largest, and the DHS + DS group was the smallest.

CONCLUSION

Compared with the other two internal fixation methods, dynamic hip screw + derotational screw (DHS + DS) showed good biomechanical stability. When Pauwels type III femoral neck fracture occurs in young adults, DHS + DS can be given priority as the preferred treatment for this type of fracture.

[Research progress of femoral neck system in treatment of femoral neck fracture in young and middle-aged patients]

Objective

To summarize the research progress of femoral neck system (FNS) in the treatment of femoral neck fracture in young and middle-aged patients.

Methods

The literature on FNS at home and abroad in recent years was extensively reviewed, and the results of mechanical and clinical studies on FNS were summarized based on clinical experience.

Results

FNS has good mechanical stability, which can reduce complications such as femoral neck shortening, internal fixation failure, and varus caused by mechanical instability. At present, FNS is mainly selected for comparison with cannulated compression screws and dynamic hip screws in clinical research. The results show that FNS has the advantages of minimally invasive, short operation time, less intraoperative fluoroscopy, earlier postoperative weight-bearing and fracture healing, and better hip function recovery.

Conclusion

As a new internal fixator, FNS has achieved satisfactory results in the current research. FNS has good mechanical advantages, which is beneficial to fracture healing and the recovery of hip joint function after operation. However, whether FNS can reduce the incidence of nonunion and osteonecrosis of the femoral head remains to be further clarified.

The use of the femoral neck system (FNS) leads to better outcomes in the surgical management of femoral neck fractures in adults compared to fixation with cannulated screws: A systematic review and meta-analysis

BACKGROUND

Intracapsular femoral neck fractures are challenging to treat, with outcomes depending on the quality of reduction, and the stability of fixation. Cannulated cancellous screws (CCS) are the most commonly used implants to fix these fractures, but failure rates are significant. The recently introduced femoral neck system (FNS) may be a better option than CCS fixation and this review attempts to compare the results.

METHODS

Four electronic databases were searched for eligible articles that had comparative data on the outcomes of fixation of adult femoral neck fractures with FNS and CCS. Data on various outcome parameters were collected. Meta-analysis was conducted using a random-effects model with 95% confidence intervals.

RESULTS

Eight studies with 509 cases having a mean age of 50.8 years were included for final analysis. FNS was found to be associated with significantly reduced complication rates (p < 0.001), decreased incidence of postoperative femoral neck shortening (p < 0.001), quicker time to fracture union (p = 0.002), and better functional outcome scores (p < 0.001) compared to cannulated screws. FNS was also associated with a shorter operating time (mean difference 6.65 min) although not statistically significant (p = 0.24). CCS group had significantly reduced mean blood loss (p < 0.001).

CONCLUSION

The available literature supports FNS as a better option for adult femoral neck fractures, with a lower complication rate, quicker union, and better clinical outcomes.

LEVEL OF EVIDENCE

Level 3.

Femoral neck system versus cannulated screws for fixation of femoral neck fracture in young adults: a systematic review and meta-analysis

PURPOSE

Femoral neck fracture treatment in young adults remains controversial. Cannulated screws (CS) and femoral neck system (FNS) are well-accepted methods for femoral neck fracture treatment; however, these methods are associated with complications. This meta-analysis aimed to evaluate the relative safety and effectiveness of CS and FNS for treating young patients with femoral neck fractures.

METHODS

We searched the following sources for studies that compared CS and FNS fixation: Cochrane library, Embase, PubMed, Web of Science, Wanfang data, China National Knowledge Infrastructure, China Biology Medicine disc, and Chinese Science and Technology Journals. The outcomes were surgical and prognostic results and complications.

RESULTS

This meta-analysis included eight studies. The pooled results revealed that the two fixation methods were similar in terms of the operation time, length of hospital stay, healing time, intraoperative blood loss, non-union, femoral head necrosis, and internal fixation cut-out. Compared with CS fixation, FNS fixation required fewer intraoperative fluoroscopies and had better Harris Hip Score, earlier weight-bearing, lower number of total complications, lesser femoral neck shortening, and lesser extent of nail retreat.

CONCLUSION

FNS fixation outperforms CS fixation in terms of intraoperative fluoroscopies, Harris Hip Score, and morbidity in young patients with femoral neck fractures. Clinicians should consider FNS as a first choice in treating femoral neck fracture in young adults, except where this approach is contraindicated.

Effect of proximal femoral nail antirotation on clinical outcome, inflammatory factors and myocardial injury markers in patients with femoral trochanteric fracture

OBJECTIVE

To compare the differences between proximal femoral nail antirotation (PFNA) and dynamic hip screw (DHS) in treatment of femoral trochanteric fracture and analyze the factors influencing recovery after PFNA treatment.

METHODS

Eighty-six patients with femoral trochanteric fracture admitted to Taizhou Hospital of Traditional Chinese Medicine between January 2019 and June 2021 were enrolled in the study and assigned into a PFNA group and DHS group (n=43 in each group) before undergoing these treatments. The clinical efficacy, inflammatory factors, and myocardial injury markers were compared between the two groups. The influencing factors on recovery after PFNA treatment were analyzed by univariate and multivariate analysis.

RESULTS

Compared to the DHS group, the PFNA group had shorter surgical time, length of stay in hospital, postoperative weight-bearing time, time of healing and detumescence, and less intraoperative blood loss (all P<0.001). The incidence of post-surgical complications with PFNA was lower than with DHS (P<0.05). The serum levels of interleukin-6, C-reactive protein and tumor necrosis factor-αof the PFNA group were lower than those of the DHS group (all P<0.05). Moreover, the serum levels of cardiac troponin T, creatine kinase-MB and myoglobin in the PFNA group were also lower than for the DHS (all P<0.05). At the first, third, and sixth months after surgery, the Harris scores for PFNA were higher than for DHS (all P<0.05). The univariate and multivariate analysis showed that instability of fracture, history of osteoporosis, excessive intraoperative bleeding, poor compliance with rehabilitation exercise, and long time from injury to surgery were risk factors for poor recovery following PFNA treatment for patients with femoral trochanteric fracture.

CONCLUSION

Compared to DHS, PFNA had better clinical efficacy and gave lower serum levels of inflammatory factors and myocardial injury markers. Fracture classification, history of osteoporosis, intraoperative amount of bleeding, compliance of rehabilitation exercise, and time from injury to surgery were closely associated with recovery following PFNA treatment.

Neck of femur fractures treated with the femoral neck system: outcomes of one hundred and two patients and literature review

Introduction

The recently developed femoral neck system (FNS) for treatment of femoral neck fractures (FNF), comprises theoretical biomechanical advantages compared to other implants. The aim of this study was to validate the safety and to report outcomes of patients treated with the FNS.

Method

A retrospective multicentric analysis of patients treated by FNS with a minimum of three months of follow-up. Details analysed from three medical centres were operative duration, estimated blood loss, initial hospitalisation duration, fixation quality as well as complications and reoperation rate. Patients who had revision surgery were compared to all other patients to identify risk factors for failure. In addition, a literature review was performed to analyse data on FNS clinical implementation and patient’s outcomes. The two data sets were combined and analysed.

Results

One-hundred and two patients were included in this study cohort with an average follow-up of seven months (range 3–27). Ten papers were included in the literature review, reporting data on 278 patients. Overall, 380 patients were analysed. Average age was 62.6 years, 52% of the fractures were classified as Gardens 1–2. Overall, the revision rate was 9.2% (14 patients diagnosed with cut-out of implant, 10 with AVN, 8 with non-union and 8 with hardware removal). For the 102 patients in the cohort risk factors for reoperation included patients age, surgeon seniority and inadequate placement of the implant.

Conclusion

This study shows that FNS is a safe treatment option for FNF. Intra-operative parameters and failure rates are comparable to previously reported rates for this implant and other frequently used implants.