Fixation of Femoral Neck Fractures Using Divergent Versus Parallel Cannulated Screws

Outcomes of three cannulated screws in a modified triangular transverse configuration for fixation of intra-capsular femoral neck fractures

BACKGROUND

Intra-capsular femoral neck fractures (FNF) are commonly encountered in trauma settings and are associated with high rates of morbidity and mortality. One of the most used methods of FNF treatment is the use of multiple cannulated screws. Many different screw constructs are reported in the literature, with no evidence of superiority of one construct over others. We present a series of patients treated by one senior surgeon with three cannulated screws positioned in a specific configuration.

MATERIALS AND METHODS

We conducted a retrospective monocentric analysis. All charts of patients hospitalized between January 2004 and June 2022 for an intra-capsular femoral neck fracture treated by three cannulated screws by the same senior surgeon were retrieved and analyzed. The clinical and radiological evaluations were performed by two independent researchers. Functional status of patients was assessed using the modified Harris Hip score (mHHS). Complications such as secondary displacement, non-union, avascular necrosis (AVN) and femoral neck shortening were all recorded.

RESULTS

A total of 38 patients met the inclusion criteria. There were 17 males and 21 females with an average age of 66.3 ± 13.6 years and a follow-up period of 16 ± 20 months. Bone union was observed in 34 (89.5%) patients. Mild shortening was observed in two patients (5.2%) with no functional limitation. Four patients (10.5%) underwent reoperations, three due to another fall and one due to AVN four years post-fracture fixation.

CONCLUSION

In our series, we demonstrate that the use of three cannulated screws in a triangular transverse configuration for fixation of intra-capsular femoral neck fractures provides excellent results with low rates of femoral neck shortening, AVN or non-union.

Gamma Nail Combined with One Cannulated Compression Screw Fixation for Treating Pauwels Type III Femoral Neck Fractures in Young and Middle-Aged Adults: Clinical Follow-Up and Biomechanical Studies

OBJECTIVE

Recently, some clinical studies have reported the use of an intramedullary nailing system for treating unstable femoral neck fractures or femoral neck fractures combined with femoral shaft fractures in young adults, and the results have indicated certain advantages. However, no study has investigated the mechanical properties of this method. We aimed to evaluate the mechanical stability and clinical efficacy of the Gamma nail combined with one cannulated compression screw (CCS) fixation for treating Pauwels type III femoral neck fracture in young and middle-aged adults.

METHODS

This study consists of two parts: a clinical retrospective study and randomized controlled biomechanical test. Twelve adult cadaver femora were used to test and compare the biomechanical properties among three fixation methods: three parallel CCS (group A), Gamma nail (group B), and Gamma nail combined with one cannulated compression screw (group C). The single continuous compression test, cyclic load test, and ultimate vertical load test were used to evaluate the biomechanical performance of the three fixation methods. We also conducted a retrospective study of 31 patients with Pauwels type III femoral neck fractures, including 16 patients with fractures fixed with three parallel CCS (CCS group) and 15 patients with fractures fixed with Gamma nail combined with one CCS (Gamma nail + CCS group). The patients were followed up for at least 3 years, and all were evaluated for surgical time (from skin incision to closure), surgical blood loss, hospital stay, and the Harris hip score.

RESULTS

In mechanical experiments, we have found that the mechanical advantages of Gamma nail fixation are not as good as those of conventional CCS fixation. However, the mechanical properties of Gamma nail fixation combined with one cannulated screw perpendicular to the fracture line are much better than those of Gamma nail fixation and CCS fixation. No significant difference was found in the incidence of femoral head necrosis and nonunion between the CCS and Gamma nail + CCS groups. Moreover, there was no statistically significant difference in the Harris hip scores between the two groups. One patient in the CCS group showed significant withdrawal of cannulated screws at 5 months after surgery, whereas in the Gamma nail + CCS group, all patients, including those with femoral neck necrosis, showed no loss of stability of the fixation.

CONCLUSION

Among the two fixation methods evaluated in this study, Gamma nail combined with one CCS fixation showed better biomechanical properties and may reduce complications associated with unstable fixation devices.

Surgical Tool Handle Vibration-Based Drilling State Recognition During Hip Fracture Fixation

Objectives

Traditional manual drilling during hip fracture fixation can easily lead to unstable fixation and vascular damage. This study aimed to investigate a safe and easy‐to‐use robot‐assisted method to automatically drill bone and distinguish critical bone drilling states with high accuracy in real‐time for the bone hole‐making process during hip fracture fixation.

Methods

A bone‐drilling robotic system was designed to automatically create holes in the femoral neck. Four fresh pig femurs were drilled at the posterosuperior femoral neck using three modes: “all‐in” (AI), “in‐out‐in” (IOI), and “percutaneous fixation” (PF). A high‐frequency accelerometer captured the generated vibrations of the drill handle, which were then transferred to a personal computer using a data acquisition card. Five bone drilling states are defined, including: “drill idling,” “initial drilling,” “in the cancellous bone,” “out the femoral neck,” and “in the cortical bone.” The harmonic distribution of the vibration signal was extracted by fast Fourier transform (FFT) and used as a critical feature to identify different drilling states. To prove the difference in the harmonic distribution at different drilling states, an independent sample t‐test was used to compare the percentage of the first harmonic amplitude in the first 10 harmonics at each drilling state. A neural network classifier was trained with the frequency spectrum as the input and the drilled state as the output to distinguish the critical bone drilling states with high accuracy in real‐time. The classifier was trained and tested on four specimens to ensure that the surgical robot could accurately identify the five drilling states.

Results

In each specimen, the harmonic distributions of the drilling vibration at different drilling modes were significantly different (p < 0.05). The average recognition accuracies of the drilling state for the four specimens were all higher than 84%. The three defined modes were distinguished with extremely high accuracies. The recognition accuracies of “in the cancellous bone” for specimens 1 to 4 were 83.2%, 84.8%, 92.9%, and 84.7%. The recognition accuracies of “in out the femoral neck” from specimens 1 to 4 are 98.2%, 88.4%, 95.8%, and 88.8%. The recognition accuracies of “in the cortical bone” for specimens 1 to 4 were 94.6%, 80.8%, 95.5%, and 85.8%.

Conclusions

The proposed robot‐assisted method can automatically distinguish five critical bone‐drilling states with high accuracy in real‐time to avoid weak fixation and damage to the lateral epiphyseal artery.

Parallel and non-parallel cannulated screw fixation complications in femoral neck fractures: A systematic review and meta-analysis

BACKGROUND

Since its introduction in the early 1960s, the multiple cannulated screw fixation method has been developed for use in femoral neck fractures (FNFs); however, the parallelism of screws remains controversial.

MATERIALS AND METHODS

MEDLINE, Embase, and the Cochrane Library were systematically searched for studies published before June 2, 2020, that compared the use of parallel and non-parallel screw fixation for the treatment of FNF. The pooled analysis was designed to identify differences between the two groups and focused on postoperative complications, including fracture nonunion and osteonecrosis of the femoral head (ONFH).

RESULTS

Over four studies, we enrolled 445 patients, including 195 patients with fixed FNF with parallel trajectory screws and 250 patients with fixed FNF with non-parallel screws. The pooled analysis showed no difference in the nonunion rates (odds ratio (OR)=0.91; 95% confidence interval (CI), 0.24-3.44; p=0.89) and no significant difference in the incidence of ONFH between parallel and non-parallel screw fixation (OR=0.74; 95% CI: 0.21-2.63; p=0.64).

CONCLUSIONS

The results of this meta-analysis reveal that screw parallelism in multiple cannulated screw fixation of FNF has no relationship with either the fracture nonunion rate or the incidence of postoperative ONFH.

LEVEL OF EVIDENCE

III; meta-analysis.

Factors Associated with Femoral Neck Shortening After Closed or Open Reduction and Screw Fixation

PURPOSE

This study aimed to evaluate the incidence of femoral neck shortening (FNS) after the treatment of displaced and non-displaced femoral neck fractures with closed or open reduction internal fixation, and determine the independent factors associated with this condition.

METHOD

The study included 81 patients who underwent internal fixation by closed or open reduction with multiple screws between 2013 and 2018 due to femoral neck fracture (FNF) and were followed up for at least 1 year. Patients were divided into two groups as with and without FNS. The patient, fracture, and surgical parameters compared between the two groups, and the factors affecting development of FNS were investigated.

RESULTS

Internal fixation was applied by closed reduction in 56 patients (69.1%) and open in 25 (30.9%). FNS was detected in 41 patients (50.6%), with the mean shortening 6.3 ± 6.4 mm. Fracture union achieved in 72 patients (89%). The mean time to fracture union was 4.3 ± 2.3 months.No statistically significant relationship found between FNS and the parameters of gender, age, smoking, reduction type, number, type and orientation of screws, Singh index, and Garden fix index (p > 0.05).However, there was significant difference between two groups regarding energy of the fracture, fragmentation, coronal angulation, Garden type, and fixation with medial buttress plate (p < 0.05).

CONCLUSION

FNS is an expected condition in FNF fixed by screws. Patients with high-energy traumas and advanced Garden types are more likely to have FNS. The use of medial plate may be effective in preventing FNS.

Screw trajectory affects screw cut-out risk after fixation for nondisplaced femoral neck fracture in elderly patients

BACKGROUND

Incidence of femoral neck fracture has risen with the aging of the population and has critical implications with regard to patient death, functional dependence, and social costs. Screw fixation using triangular configurations and calcar placement are still the preferred treatment for nondisplaced femoral neck fracture, to reduce the risk of loss of reduction and nonunion. However, this method is still controversial in terms of the effects of screw trajectory, including parallel or nonparallel configurations, on fixation of femoral neck fractures. This study aimed to compare the incidence of complications between patients who have undergone fixation with a parallel or a nonparallel screw trajectory.

METHODS

We retrospectively analyzed 55 patients who were older than 60 years and diagnosed with nondisplaced femoral neck fracture from March 2014 to March 2016, and who were treated with cannulated screw fixation in our institution. Patient demographics, radiographic parameters including reduction quality, screw trajectory, and complications during the follow-up period were all evaluated.

RESULTS

The overall complication rate for screw fixation in elderly patients was 23.6%, and screw cut-out was the most common complication, occurring in 14.5% of all enrolled patients. Also, we found that screw cut-out occurred in more osteoporotic patients, and all screw cut-outs were in groups treated with a nonparallel screw trajectory. However, parallel screw fixation was inclined to back out more after fracture healing and had a lower risk of postoperative screw cut-out.

CONCLUSIONS

Our results suggested that fixation with nonparallel screws for nondisplaced femoral neck fracture in elderly and osteoporotic patients might interfere with shortening of the femoral neck along with fracture healing, leaving patients at risk of postoperative screw cut-out from the femoral head.

[Effectiveness of F-shaped screw fixation technique in treatment of Pauwels type femoral neck fractures]

Objective

To summarize the effectiveness of F-shaped screw fixation technique in treatment of Pauwels type Ⅲ femoral neck fractures.

Methods

Between January 2013 and December 2016, 43 patients with Pauwels type Ⅲ femoral neck fractures were treated with F-shaped screw fixation technique. There were 32 males and 11 females with an average age of 38.9 years (range, 20-55 years). The fractures located on the left side in 21 patients and on the right side in 22 patients. The cause of injury included traffic accident in 19 patients and falling from height in 24 patients. There were 25 patients of Garden type Ⅲ and 18 of Garden type Ⅳ. The time from injury to operation was 2-3 days (mean, 2.2 days). These data were recorded, including operative time, fluoroscopy time, postoperative hospital stay, quality of reduction, postoperative complications (nonunion, varus deformity, femoral neck shortening, avascular necrosis of femoral head, screws back-out), and Harris scores.

Results

The operative time was 28-45 minutes (mean, 37.5 minutes). The fluoroscopy time was 13-20 seconds (mean, 14.7 seconds). The postoperative hospital stay was 2-3 days (mean, 2.7 days). All incisions healed by first intention. All patients were followed up 18-58 months with an average of 38.7 months. All patients have anatomical reduction of fractures. Fracture healing occurred in 42 patients; the union time was 3-5 months with an average of 3.6 months. Nonunion occurred in 1 patient who was treated with total hip arthroplasty. Of the 42 patients with fracture healing, 11 cases had a femoral neck shortening, 9 cases had varus deformity, 3 cases had avascular necrosis of femoral head, and 8 cases had screws back-out. There was no significant difference in complication incidences between Garden type Ⅲ fractures and Garden type Ⅳ fractures ( P>0.05).

Conclusion

Treatment of femoral neck fractures by using the F-shaped screw fixation technique, can achieve satisfactory effectiveness with less postoperative complication.

Risk Factors for Neck Shortening in Patients with Valgus Impacted Femoral Neck Fractures Treated with Three Parallel Screws: Is Bone Density an Affecting Factor?

Purpose

The purpose of this study is to analyze the relationship between significant femoral neck shortening (SFNS) and bone density after three parallel screw fixation in valgus impacted femoral neck fracture, and to analyze the risk factors for SFNS.

Materials and Methods

This is retrospective study of 83 patients. We performed univariate analysis for patient information, bone density, fracture configuration and screw position divided into SFNS group (n=13) and non-SFNS group (n=70) and performed multivariate analysis using logistic regression model. We also analyzed the relationship between SFNS and complications such as osteonecrosis of femoral head and nonunion.

Results

There was a significant difference in age, screw non-parallelism and bone mineral density of intertrochanteric and total hip area in the univariate analysis between the two groups (P<0.05). In multivariate analysis, old age (odds ratio [OR], 1.10; 95% confidence interval [CI], 1.03-1.21) and screw non-parallelism (OR, 2.95; 95% CI, 1.44-6.59) were significant risk factors for SFNS. The incidence of SFNS was significantly higher in the complication group (P=0.027).

Conclusion

Bone density did not significantly affect SFNS in valgus impacted femoral neck fractures treated with three parallel screws. The risk factors of SFNS were old age and screw non-parallelism. Therefore, we recommend using other fixation method to prevent SFNS in older ages and making the screw position as parallel as possible when performing screw fixation in valgus impacted femoral neck fracture.

Non-parallel screw fixation for femoral neck fractures in young adults

INTRODUCTION

Current literature shows divergence of views regarding screws positioning in femoral neck fractures fixation. The goal of this study is to evaluate the efficiency of divergent screw fixation for fracture neck of femur (NOF).

METHODS

The study was conducted at an academic Level 1 Trauma Center. This is a retrospective study conducted from October 2013 to October 2016. The study included 41 patients (33 males, 8 females) suffering from fracture NOF who were fixed using BDSF technique (26 within 24 h. & 15 after 24 h.). The average age was 41.5 y (23-49 y). According to Garden classification; 17 patients (41.5%) were type 4, 24 patients (58.5%) were type 3. According to Pauwel's classification; 8 cases (19.5%) were type III, 25 cases (61%) were type II & 8 cases (19.5%) were Type I. Thirty-six cases (88%) were trans-cervical, 4 Sub-capital (9.5%) and 1 (2.5%) Basi-cervical. Six patients had comminution at the fracture site. We evaluated radiographic outcomes of union, femoral neck shortening, screws back-out & femoral head avascular necrosis (AVN). We also evaluated functional outcome using the Harris hip score. Follow-up was 24 months on average (ranging from 20 to 29 months).

RESULTS

One patient was lost during the follow up, the remaining 40 cases gave the following results regarding union: 38 united (within 3-4 months), 2 patients were un-united & one of them developed AVN. Twenty-seven patients (71%) had femoral neck shortening <5 mm, 8 patients (21%) had shortening 5-10 & 3 patients (8%) had shortening >10 mm. Shortening was on average 3 mm (0-15). Screws back-out distance was on average 4 mm (0 to16). Patients with mild femoral neck shortening had Harris hip score of 96 on average (92-100), those with moderate shortening had a score of 75 on average (72-79), those with severe shortening had a score of 62 on average (56-68).

CONCLUSION

The Authors believes this method provides better union rate & less incidence of femoral neck shortening than that of the conventional inverted triangle screws configuration reported in literature. However multi-center studies & long term follow-up is needed to fully evaluate this method.

Tips and tricks for ORIF of displaced femoral neck fractures in the young adult patient

Femoral neck fractures in the young adult are a less common, but potentially functionally significant injury commonly occurring after high-energy trauma. The management goals of these injuries are the maintenance of a native hip joint absent avascular necrosis and nonunion. The primary determinant to this end is an anatomic reduction in displaced fractures with stable fixation. In this paper, the authors provide a set of technical tips and tricks to aid orthopedic surgeons in the surgical management of these injuries while reviewing the most recent literature available to inform clinical decision making. The paper includes the recommendations of the authors from the Denver Health Orthopaedic Trauma Service.

Femoral neck fractures: current management

Femoral neck fractures are a commonly encountered injury in orthopaedic practice and result in significant morbidity and mortality. It is essential that surgeons are able to recognize specific fracture patterns and patient characteristics that indicate the use of particular implants and methods to effectively manage these injuries. Use of the Garden and Pauwels classification systems has remained the practical mainstay of femoral neck fracture characterization that help dictate appropriate treatment. Operative options include in situ fixation, closed or open reduction and internal fixation, hemiarthroplasty, and total hip arthroplasty. Recent reports demonstrate diversity among orthopaedic surgeons in regard to the optimal treatment of femoral neck fractures and changing trends in management. The present discussion focuses on the current indications and methods for femoral neck fracture management to provide direction with respect to appropriate and effective care of these injuries.