Is new always better: comparison of the femoral neck system and the dynamic hip screw in the treatment of femoral neck fractures

Outcomes of internal fixation with Femoral Neck System (FNS) for intracapsular femoral neck fractures

Background

Internal fixation of hip fractures is associated with high reoperation rates. This study investigated the reoperation rates after internal fixation with the femoral neck system (FNS).

Materials and Methods

A single-institution cohort study was conducted on patients aged 18 years or older who sustained intracapsular femoral neck fractures and underwent internal fixation with a fixed-angle implant. Surgeons, patients, and investigators were not blinded. The primary outcome was any hip reoperation at the final follow-up. Secondary outcomes were to characterize a cohort of patients regarding demographics, fracture classification, intraoperative findings, postoperative fracture complications and union rates, and postoperative pain.

Results

This study found that internal fixation with FNS for intracapsular femoral neck fractures was associated with a 23% rate of revision surgery. Of the initial 94 patients who received FNS internal fixation, 44 patients were included for analysis; of those, 10 patients underwent revision surgery. Patients had a 22% rate of in-hospital medical adverse events with a 30-day readmission rate of 9%. Increasing body mass index was associated with increased revision rates (P = 0.037). Patients who sustained displaced femoral neck fractures had a significant decrease in SF-12 Mental Health Composite, SF-12 Physical Health Composite, and quality-of-life subscale scores.

Conclusions

The FNS is a viable alternative for internal fixation of intracapsular femoral neck fractures. The observed rate of revision after internal fixation was comparable with previously published outcomes following fixation with cannulated screws and sliding hip screws.

Level of Evidence

Level IV, Therapeutic Study.

Two-year outcomes of internal fixation with femoral neck system in patients with femoral neck fracture in an Asian population

Background

Femoral neck fractures (FNF) are one of the most common fractures, with a projected increase in incidence with population growth and ageing. The Femoral Neck System (FNS) launched in 2019 was developed specifically for fixation of FNF with the purported advantages of providing both angular and rotational stability. We report our experience with the FNS and evaluate its effectiveness and associated complications.

Methods

A retrospective case series of 50 patients who underwent surgical fixation for FNF from August 2020 to October 2021 using the FNS in two Singapore tertiary institutions with at least 2 years follow-up were included. Clinical data (patients' demographics, fracture classification, intra-operative and post-operative complications) were reviewed. Radiological analysis assessed the pre- and immediate post-operative garden alignment index (GAI) and presence of femoral neck shortening at 3 months.

Results

The mean age was 63.5 years (SD 16.9, range 26-92). Five (10 %), 34 (68 %) and 11 (22 %) were ASA 1, 2 and 3 respectively. Twenty-four (48 %), 16 (32 %), 4 (8 %), and 6 (12 %) patients sustained Garden's 1, 2, 3 and 4 FNF respectively. The mean operative duration was 66.2 min (SD 20.5) and length of stay was 6.9 days (SD 4.6).The post-operative improvement in garden alignment index (GAI) was a mean of 9.1° (p < 0.001) on lateral view. The mean femoral neck shortening was 1.97 mm (SD 5.3) at 3 months. There were no intra-operative complications. Post-operatively, 1 (2 %) patient required blood transfusion, 1 (2 %) patient had implant cut-out and non-union managed non-operatively, 2 (4 %) patients developed avascular necrosis and required revision to total hip replacements. There were two (4 %) cases of 1-year mortality.

Conclusion

The FNS achieved good outcomes with low rates of complications. The promising results justify its continued use and further evaluation in comparison to other devices.

Global trends of Pauwels type III femoral neck fractures: bibliometric analysis and visualized study

Background

Pauwels type III femoral neck fractures, as a serious type of femoral neck fractures, have brought about a heavy economic burden on families and society for the high disability rate. Through bibliometric research and visualized analysis, this study aimed at elucidating the global research status of Pauwels type III femoral neck fractures to date, and predicting the future research trends in this field.

Methods

Publications and associated information on Pauwels type III femoral neck fractures to date were retrieved from Web of Science Core Collection, and by VoSviewer and R package "bibliometrix", bibliometric analysis and visual presentation was conducted.

Results

By retrieval, a total of 98 studies were refinedly extracted, and the volume of publications in this field increased year-over-year. China ranked first in terms of total publication volume and H-Index, with its total citation records second only to the United States. The country with the highest average citation frequency was Switzerland. SHANGHAI JIAO TONG UNIVERSITY was the most productive research institution. Among the authors in this field, Li, Jiantao had published the most researches. INJURY INTERNATIONAL JOURNAL OF THE CARE OF THE INJURED and JOURNAL OF ORTHOPAEDIC TRAUMA were the two magazines with the highest publication volume, total citation records, and H-index. According to keywords co-occurrence analysis, the research content in the past 24 years is mainly divided into four different dimensions. Finite element analysis, femoral neck system, medial buttress plate, cannulated screws, hip screw, open reduction, complications are hot topics for future research.

Conclusions

According to the global trends analysis of publications production, Pauwels type III femoral neck fractures are receiving increasing attention and input from scholars. China has made the greatest scientific research contribution among countries, but its academic quality should be improved further. The modified therapeutic methods designed for addressing the complications of traditional internal fixation for Pauwels III femoral neck fractures will be the future research hotspot.

Revision rate of displaced femoral neck fractures in non-elderly adults: a retrospective comparative study of the femoral neck system and cannulated screws

BACKGROUND

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).

METHODS

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.

RESULTS

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).

CONCLUSIONS

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.

The synthes femoral neck system (FNS): a technical tip and case series

The femoral neck system (FNS) was recently introduced for treatment of femoral neck fractures. A novel feature is an anti-rotation screw with a diverging design from the neck bolt to provide rotational stability. Using the 4 Nm torque limiting screwdriver might cause the incomplete insertion of the screw specifically in dense or sclerotic bone. A nontorque limiting manual screwdriver should be used to complete the insertion and locking of the screw to prevent this error. We present series of seven cases with incomplete insertion of the anti-rotation screw in patient with femoral neck fractures treated with the FNS.

[Management of the cut-out of various forms of osteosynthesis for proximal femoral fractures]

Proximal femoral fractures are a common type of injury in older people. A cut-out of the femoral neck screw after initial osteosynthetic surgery of proximal femoral fractures is a frequent and feared complication. There could be different causes for cut-outs. Osteoporosis and necrosis of the femoral head could be biological reasons for cut-outs; however, mechanical factors, such as reduction, implant position and morphological characteristics of fractures also have a major influence on the cut-out rate. The treatment of the cut-out is often complex and depends on the destruction of the femoral head and the acetabulum. If the bone quality is still good and the head is not completely destroyed, a reosteosynthesis can be performed. Conversion to an endoprosthetic replacement is often the only possibility. Endoprosthetic treatment is often complex and associated with a high morbidity.

Clinical efficacy of Femoral Neck System for treatment of unstable femoral neck fractures in young adults

OBJECTIVE

This study was performed to evaluate the mid-term clinical efficacy of the Femoral Neck System (FNS) (DePuy Synthes, Zuchwil, Switzerland) in treating young patients with unstable Pauwels type III femoral neck fractures.

METHODS

We performed a retrospective observational analysis of 21 young adults treated with the FNS. Clinical outcomes were assessed based on fracture reduction quality, Harris hip scores, and postoperative complication rates.

RESULTS

The study comprised 21 patients with a mean age of 35 years (range, 20-50 years) who were followed for a mean duration of 22.8 months (range, 16-30 months). Closed reduction was unfeasible in three (14.3%) patients, each of whom required open reduction. Notable postoperative complications were avascular necrosis in two (9.5%) patients, nonunion in one (4.7%), and implant failure in one (4.7%). Each of these complications led to the requirement for total hip arthroplasty.

CONCLUSION

The favorable mid-term clinical outcomes of this study indicate that the FNS is a potentially effective treatment modality for young individuals with unstable Pauwels type III femoral neck fractures.

Comparative Short-Term Outcomes of Femoral Neck System (FNS) and Cannulated Screw Fixation in Patients with Femoral Neck Fractures: A Multicenter Study

Background

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.

Methods

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.

Results

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.

Conclusions

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.

Revision ratio after Femoral Neck System implantation for hip fracture treatment: a retrospective cohort analysis

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.

Investigation of dynamic hip plate screw systems in different lengths with finite element analysis

Objectives

Dynamic systems aim to create an environment that encourages bone healing while minimizing stress shielding, which is a phenomenon where the bone loses density due to a lack of stress during the healing process. In this study, it was aimed that the stress distributions on plates of different lengths in the dynamic hip plate screw system were investigated.

Materials and methods

In our study, the human proximal femur model (3-D) obtained from computerized tomography was transferred to Finite Element Analysis (FEA) computer simulation. Plates with 2-4-6 holes were placed on the knitted bone model. The models used in this study were mainly determined as five components: cortical-cancellous bone, lateral plate, cortical screws, and compression neck screws. A 1 mm intertrochanteric fracture area was created from the trochanter major region.

Results

When plates of different lengths were applied, there was no significant difference in the stress in the compression screw and the chamber it was located in.It shows that when a 2-hole plate is used, the stress will be high, especially between the lower cortical screw and the cortex. In these three groups, it was observed that the stress points were in at least 6-hole plates.

Conclusion

The results of this study showed that the shorter the plate applied, the greater the stress on the plate and cortical screws in the femur diaphysis.

Application of robot navigation system for insertion of femoral neck system in the treatment of femoral neck fracture

PURPOSE

To evaluate the short-term clinical efficacy and advantages of surgery robot positioning system for insertion of Femoral Neck System (FNS) in the treatment of femoral neck fractures.

METHODS

The clinical data of 52 patients with Femoral neck fracture (FNF) who had been treated with FNS between June 2020 and September 2021 were retrospectively analyzed. Among them, 26 patients were treated with traditional FNS (control group), while 26 additional patients were treated with FNS assisted by an orthopaedic robot positioning system (study group). The operation duration, frequency of key-guide needle placement, intraoperative blood loss, incision length, fracture healing rate, fracture healing time, and the Harris scores at the last follow-up were calculated and compared between the 2 groups.

RESULTS

The study group had shorter operation duration, fewer numbers of placing the key-guide needle, less intraoperative blood loss, and smaller surgical incisions than the control group (all, P < 0.05). There was no significant difference in the rate of fracture healing rate between the 2 groups (P = 0.47), while the fracture healing duration of the study group was shorter than that of the control group (P = 0.03). At the last follow-up, compared with the control group, the Harris score and the number of excellent and good ratings were significantly higher in the study group (all, P < 0.05).

CONCLUSIONS

Using orthopaedic surgery robot positioning system-assisted FNS in the treatment of FNFs can effectively improve the efficiency of surgery, shorten operation time, and reduce the number of placing the key-guide needle, intraoperative blood loss, and operative trauma. Simultaneously, it shortens the duration of fracture healing and improves the recovery of hip function.

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.

Treatment of Femoral Neck Fractures in the Elderly: A Survey of the Korean Hip Society Surgeons

Purpose

This study examined the methods for treatment of femoral neck fracture (FNF) preferred by members of the Korean Hip Society (KHS) and identified factors that influence decisions regarding the surgical intervention of choice.

Materials and Methods

A total of 97 members of the KHS responded to the 16-question survey which included questions about the mean number of surgeries performed each month for treatment of femoral neck fractures, the cut-off age for deciding between internal fixation and arthroplasty, the implant used most often, usage of cement, and factors influencing each decision.

Results

The mean cut-off age used when deciding between internal fixation and arthroplasty was 64 years old. Hemiarthroplasty (HA) (70%) was the most preferred option for treatment of displaced FNFs in cases where arthroplasty was indicated (total hip arthroplasty [THA] 19% and dual mobility THA 11%). The main reasons for selection of arthroplasty over reduction with internal fixation were age and pre-fracture ambulatory status. Pre-trauma ambulatory status and/or sports activity were the main factors in selection of HA over THA. Cement was used by 33% of responders. Poor bone quality and a broad femoral canal were factors that influenced the usage of cement.

Conclusion

Management of FNFs in the elderly is a major health problem worldwide; thus, remaining alert to current trends in treatment is essential for surgeons. The mean cut-off age used in deciding between internal fixation and arthroplasty was 64 years old. HA is the preferred method for treatment of displaced FNFs for members of the KHS.

Clinical performance of the Femoral Neck System within 1 year in 125 patients with acute femoral neck fractures, a prospective observational case series

INTRODUCTION

Osteosynthesis of femoral neck fractures (FNFs) is an important treatment option, especially for younger patients. We aimed to assess the rate of early implant-related complications in FNF osteosynthesis using the Femoral Neck System (FNS).

PATIENTS AND METHODS

Consecutive patients diagnosed with displaced or nondisplaced FNFs were treated with FNS in this prospective, observational, multicenter investigation. Patients were followed up for minimally 3 months and up to 12 months if radiologic bone union and no pain was not achieved beforehand. Predefined treatment-related adverse events (AEs, defined as implant failure, loss of reduction, iatrogenic fractures, deep infection, and surgical revision), radiologic bone union, and patient-reported Harris hip score (HHS) and EQ-5D-5L index score were assessed.

RESULTS

One hundred and twenty-five patients were included in the study. Thirty-eight (30.4%) fractures were displaced (Garden III and IV), and 37 (29.6%) were vertical fractures (Pauwels type III). Predefined treatment-related AE rate at 3 months was 8 patients, 6.4% (95% CI, 2.8-12.2), and at 12 months, 11 patients, 8.8% (95% CI, 4.5-15.2). Cumulative incidences of bone union were 68% at 3 months, 90% at 6 months, and 98% at 12 months. The mean changes of HHS and EQ-5D-5L index score between preinjury and at 12 months were -7.5 (95% CI, [ - 21.1] to [6.2]) and  - 0.03 (95% CI, [ - 0.21] to [0.15]), respectively; neither were statistically significant.

CONCLUSION

The current study on osteosynthesis of FNFs with the FNS resulted in treatment-related complication rates of 6.4% (95% CI, 2.8-12.2) at 3 months and 8.8% (95% CI, 4.5-15.2) at 12 months. On average, patients returned to preinjury function and quality of life. The current study may also indicate that the conventional wisdom of treating stable FNF in patients aged between 60 and 80 years with osteosynthesis may need to be reconsidered.

REGISTRATION

The study is registered with ClinicalTrials.gov (registration number: NCT02422355).

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.

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.