Rating of internal fixation and clinical outcome in displaced femoral neck fractures: a prospective multicenter study

Femoral neck system reduces surgical time and complications in adults with femoral neck fractures: A systematic review and meta-analysis

PURPOSE

Femoral neck fractures (FNF) in adults are conventionally managed with surgical options. This paper is aimed to assess the safety, and functional outcomes of the novel Femoral neck system (FNS) for FNF treatment in adult population.

METHODS

An organized quest of four literature databases (PubMed, Scopus, Web of Science, and Cochrane Library) was performed on March 1, 2022 using the term "femoral neck system". Fixed or random-effect meta-analysis was used to analyse the outcome measures after selecting relevant studies and assessing their quality. Heterogeneity was considered when calculating pooled effect sizes and 95% confidence ranges.

RESULTS

On comparing FNS with cannulated cancellous screws (CCS) or other methods, in a total of 762 patients (351 FNS and 411 CCS) in the 11 comparative studies considered for meta-analysis, blood loss was pointedly higher overall in the FNS group, mean difference 115.77 ml; 95% CI 3.11 ml, 28.42 ml; test of overall effect: z = 1.68, p = 0.09); with considerable heterogeneity. However, in the FNS group the operative time was substantially lower (Mean difference -7.91 min; 95% CI -15.01, -0.80; test of overall effect: z = 2.18, p = 0.03, with marked heterogeneity). Moreover, complications such as infections, non-union, osteonecrosis, implant cut-out were significantly lower in the FNS group with a Mantel Haenszel Odds ratio of 0.20 (95% CI 0.12, 0.34: Z = 6.01, p < 0.0001).

CONCLUSION

Keeping in mind the heterogenicity of the studies, -management of adult patients with FNF with FNS can provide results comparable to traditional fixation methods with significantly lower rate of complications.

Biomechanical comparison of the femoral neck system versus InterTan nail and three cannulated screws for unstable Pauwels type III femoral neck fracture

BACKGROUND

There are a variety of internal fixation methods for unstable femoral neck fractures (FNFs), but the best method is still unclear. Femoral neck system (FNS) is a dynamic angular stabilization system with cross screws, and is a new internal fixation implant designed for minimally invasive fixation of FNFs. In this study, we conducted a biomechanical comparison of FNS, InterTan nail and three cannulated screws for the treatment of Pauwels III FNFs and investigate the biomechanical properties of FNS.

METHODS

A total of 18 left artificial femurs were selected and randomly divide into Group A (fixation with FNS), Group B (fixation with InterTan nail) and Group C (fixation with three cannulated screws), with 6 specimens in each group. After creating Pauwels type III FNF models, the specimens in each were tested with non-destructive quasi-static tests, including torsion, A-P bending and axial compression tests. The average slope of the linear load-deformation curve obtained from quasi-static tests defines the initial torsional stiffness, A-P bending stiffness, and axial compression stiffness. After cyclic loading test was applied, the overall deformation of models and local deformation of implant holes in each group were assessed. The overall deformation was estimated as the displacement recorded by the software of the mechanical testing apparatus. Local deformation was defined as interfragmental displacement. Data were analyzed by one-way analysis of variance (ANOVA) followed by Bonferroni post hoc test using the SPSS software (version 24.0, IBM, New York, NY, USA). Correlation analysis was performed using Pearson's correlation analysis.

RESULTS

Group B exhibited significantly higher axial stiffness and A-P bending stiffness than the other two groups (P < 0.01), while Group A had significantly higher axial stiffness and A-P bending stiffness than Group C (P < 0.01). Groups A and B exhibited significantly higher torsional stiffness than Group C (P < 0.01), no statistical significance was observed between Groups A and B (P > 0.05). Group B exhibited significantly lower overall and local deformations than the other two groups (P < 0.01), while Group A had significantly lower overall and local deformations than Group C (P < 0.01). Correlation analysis revealed positive correlation between axial stiffness and A-P bending stiffness (r = 0.925, P < 0.01), torsional stiffness (r = 0.727, P < 0.01), between torsional stiffness and A-P bending stiffness; negative correlation between overall, local deformations and axial stiffness (r = - 0.889, - 0.901, respectively, both P < 0.01), and positive correlation between the two deformations (r = - 0.978, P < 0.01).

CONCLUSION

For fixation of unstable FNFs, InterTan nail showed the highest axial stiffness and A-P bending stiffness, followed by FNS, and then three cannulated screws. Torsional stiffness of FNS was comparable to that of the InterTan nail. FNS, as a novel minimally invasive implant, can create good mechanical environment for the healing of unstable FNFs. Clinical studies are needed to confirm the potential advantages of FNS observed in this biomechanical study.

Femoral neck system versus inverted cannulated cancellous screw for the treatment of femoral neck fractures in adults: a preliminary comparative study

BACKGROUND

The femoral neck system (FNS) may be a valid alternative for treating femoral neck fractures, but few studies have compared the outcomes between FNS and cannulated cancellous screws. This study aimed to compare the clinical efficacy and complications of FNS with those of inverted cannulated cancellous screws (ICCS) for the treatment of femoral neck fractures in adults.

METHODS

This retrospective study evaluated patients with femoral neck fractures who underwent FNS or ICCS internal fixation between June 2019 and January 2020. The operative time, intraoperative blood loss, number of fluoroscopies, length of surgical incision, length of hospital stay, time to fracture healing, and other indicators were compared between the two groups. The incidence of complications such as nonunion, avascular necrosis of the femoral head, loosening of the internal fixation, and shortening of the femoral neck during follow-up was also assessed in both groups.

RESULTS

Among the 92 patients included, 47 and 45 patients were categorized into the FNS and ICCS groups, respectively. Follow-up ranged from 14 to 24 months. There were no significant between-group differences in sex, age, side of the injured limb, and type of fracture and in operative time, intraoperative blood loss, incision length, and length of hospital stay (all P > 0.05). The incidence of complications such as fracture nonunion, avascular necrosis of the femoral head, and screw loosening was also comparable between the two groups. However, the number of fluoroscopies was significantly lower in the FNS group than in the ICCS group (P < 0.05). The fracture healing time was also significantly lower in the FNS group than in the ICCS group (P < 0.05). Furthermore, the femoral neck shortening and Harris hip score at the last follow-up were significantly better in the FNS group than in the ICCS group (P < 0.05).

CONCLUSIONS

FNS for femoral neck fractures improves hip functional recovery and reduces the femoral neck shortening rate and fluoroscopy exposure postoperatively. Thus, FNS can be an alternative to ICCS for the treatment of femoral neck fractures.

Femoral Neck Fracture Fixation with a Medial Buttress Plate That Led to Impingement with Hip Flexion: A Case Report

CASE

A 47-year-old man with an isolated femoral neck fracture was treated with open reduction and internal fixation with a medial femoral neck buttress plate and a dynamic hip screw. Union was achieved without osteonecrosis of the femoral head. However, hip arthroscopy that was performed for persistent hip pain following the fracture union revealed an intra-articular impingement of the buttress plate and a substantial anterior acetabular chondral injury.

CONCLUSIONS

To our knowledge, this is the first reported complication associated with the application of a medial buttress plate for a femoral neck fracture. This case report may help surgeons who employ this technique to avoid a similar complication.

Factors Influencing the Outcome of Osteosynthesis in the Fracture of the Femoral Neck in Young Adult Patients

Objectives  To evaluate the factors that influence the outcome of osteosynthesis after closed reduction of the fracture of the femoral neck in young adult patients.

Methods  A retrospective study was conducted, reviewing the data of patients operated in a large orthopedic hospital from 2003 to 2011; a total of 81 patients met the inclusion criteria. The time interval between the fracture and the surgery, the initial fracture deviation, the quality of the reduction, and the placement of the implant were evaluated.

Results  The present study observed a strong relationship between the quality of the reduction and therapeutic success. The degree of the initial deviation and the time elapsed between the initial trauma and the osteosynthesis did not influence the surgical outcome regarding bone consolidation. The correct positioning of the implants was associated with a satisfactory evolution in the postoperative period.

Conclusion  The quality of the reduction and the positioning of the implants are factors that influence the results of osteosynthesis in fractures of the femoral neck in young adult patients.

High Reliability of a Scoring System for Implant Position in Undisplaced Femoral Neck Fractures

OBJECTIVES

The aim of this study was to evaluate the intrarater and interrater reliability of a scoring system for internal fixation (SIFA) in undisplaced femoral neck fractures (FNF).

DESIGN

A reproducibility study with a historical consecutive cohort.

SETTING

The patients were all treated at a level one trauma hospital.

PATIENTS/PARTICIPANTS

A cohort of patients with FNF, treated with 2 parallel implants, was retrieved using a local county register, and the cohort was assessed for undisplaced FNF until the desired sample size was reached. One hundred two patients had their x-ray images reviewed 2 times with a minimum 14 days interval, by 3 raters, all blinded for each other's results, and an independent person analyzed the data with unweighted kappa statistics.

MAIN OUTCOME MEASUREMENTS

Implant positions on the first postoperative anterior-posterior and axial radiographs were first visually assessed, then objectively measured according to SIFA, which consists of 5 individual measurements; screw tip distance, screw femoral shaft angle, inferior screw calcar distance, and screw position in the femoral head in the anterior-posterior and axial radiographs.

RESULTS

Visually assessed implant position gave intrarater kappa results for the individual components of SIFA at 0.40-0.75 (rater 1), 0.75-0.98 (rater 2), and 0.69-0.83 (rater 3), with interrater kappa results at 0.18-0.80 (combined range). Objectively measured implant position for the individual components of SIFA gave intrarater kappa results at 0.56-1.0 (rater 1), 0.74-0.89 (rater 2), and 0.81-0.94 (rater 3), with interrater kappa results at 0.56-0.85 (combined range). The overall SIFA score has similar higher intrarater and interrater results for the measured (0.51-0.78) compared with the visual assessment (0.13-0.78). The assessment in the axial view of the screw position in femoral head had the largest difference of acceptable positioning, when comparing visual assessment with the measured.

CONCLUSIONS

The SIFA demonstrates substantial intrarater and interrater reliability (kappa 0.51-0.78), when raters make measurements of radiographs, but lower reliability (kappa 0.13-0.78) when raters visually assess the radiographs without measuring. The SIFA should be assessed on a large cohort, for correlation with clinical evaluation.

Osteonecrosis of the femoral head, nonunion and potential risk factors in Pauwels grade-3 femoral neck fractures: A retrospective cohort study

The present study was to analyze clinical outcome of Pauwels grade-3 femoral neck fractures treated by different surgical techniques. Potential risk factors associated with nonunion and osteonecrosis of the femoral head (ONFH) were investigated as well. The retrospective study comprised of 67 sequential patients treated between January 2008 and December 2011. Patients with Pauwels grade-3 femoral neck fractures were treated by operative reduction and internal fixation. Cannulated screws (CS) were used in 46 patients, dynamic hip screw plus CS (DHS+CS) in 14, and locking compression plate (LCP) for proximal femur in 7. Reduction quality was assessed according to Haidukewych criteria. Postoperative radiographic examinations were conducted to observe fracture healing. Fracture displacement, comminution, fashion of internal fixation, and the sliding effect were analyzed, regarding the incidence of nonunion and ONFH. All patients had a follow-up of 21.6 ± 6.0 months on average. The phenomenon of sliding effect was observed in 16 cases (23.9%). In terms of reduction quality, 64 cases were graded as excellent, 2 were good, and 1 was poor. ONFH was presented in 15 cases (22.4%) and nonunion was found in 8 (11.9%), with 1 patient had ONFH and nonunion concomitantly. Profound hip contour was preserved in 45 cases (67.2%). The fashion of internal fixation yielded different results regarding ONFH and nonunion, whereas the effects of fracture displacement, comminution, and the sliding effect were not significant. ONFH and nonunion were common complications following Pauwels grade-3 femoral neck fractures. Higher incidence of ONFH in DHS+CS and of nonunion in the LCP group should be noted.

Application of a medial buttress plate may prevent many treatment failures seen after fixation of vertical femoral neck fractures in young adults

Femoral neck fractures in young adults with normal bone are mostly vertically oriented and may have variable amounts of comminution, which result from shearing forces during high-energy trauma. These factors play a role in the high rate of complications after this injury, including nonunion, malunion, failure of fixation, and avascular necrosis. These problems often occur together and inter-relate, for example, nonunion or malunion frequently result from fixation failure and varus collapse of the femoral head after reconstruction. The orthopaedic surgeon's goals of obtaining and maintaining anatomic reduction until bony union have been addressed by a number of surgical approaches and fixation constructs, however, complications are still common and no consensus exists on how these problematic fractures may be best treated. For optimal treatment of vertical femoral neck fractures, anatomic reduction must be achieved and fixation must be able to resist the high shear forces across the fracture with hip motion, weight-bearing, and muscle tone. Buttress plate fixation is a common method for stabilizing fractures that require resistance to shear forces and stands as one of the basic principles of fracture care. This technique has not been widely applied to this injury pattern. We propose that the concepts of modern fracture care should be applied together for vertical femoral neck fractures in young adults. Specifically, we propose that anatomic reduction and fixation of vertically oriented femoral neck fractures with the addition of a medial buttress plate to resist shearing forces will improve on the historically high rate of complications after these difficult injuries.

Predictors of early failure in young patients with displaced femoral neck fractures

INTRODUCTION

This study compares early failure rates of sliding hip screw (SHS) and cannulated screw (CS) constructs in young patients.

METHODS

Patients <60 years of age, with displaced femoral neck fractures treated with CS or SHS fixation were included. Primary outcome was failure within 6 months.

RESULTS

One patient (3%) with SHS fixation and 6 patients (21%) with CS fixation failed within 6 months (P = 0.04). Regression analysis demonstrated type of fixation (P = 0.005) and reduction quality (P = 0.04) are independent predictors of early failure.

CONCLUSIONS

SHS constructs demonstrate a significantly lower short-term failure rate than CS constructs.

Low bone mineral density is not related to failure in femoral neck fracture patients treated with internal fixation

BACKGROUND AND PURPOSE

Internal fixation (IF) in femoral neck fractures has high reoperation rates and some predictors of failure are known, such as age, quality of reduction, and implant positioning. Finding new predictors of failure is an ongoing process, and in this study we evaluated the importance of low bone mineral density (BMD).

PATIENTS AND METHODS

140 consecutive patients (105 females, median age 80) treated with IF had a dual-energy X-ray absorptiometry (DXA) scan of the hip performed median 80 days after treatment. The patients' radiographs were evaluated for fracture displacement, implant positioning, and quality of reduction. From a questionnaire completed during admission, 2 variables for comorbidity and walking disability were chosen. Primary outcome was low hip BMD (amount of mineral matter per square centimeter of hip bone) compared to hip failure (resection, arthroplasty, or new hip fracture). A stratified Cox regression model on fracture displacement was applied and adjusted for age, sex, quality of reduction, implant positioning, comorbidity, and walking disability.

RESULTS

49 patients had a T-score below -2.5 (standard deviation from the young normal reference mean) and 70 patients had a failure. The failure rate after 2 years was 22% (95% CI: 12-39) for the undisplaced fractures and 66% (CI: 56-76) for the displaced fractures. Cox regression showed no association between low hip BMD and failure. For the covariates, only implant positioning showed an association with failure.

INTERPRETATION

We found no statistically significant association between low hip BMD and fixation failure in femoral neck fracture patients treated with IF.

Adjudicating outcomes: fundamentals

The adjudication of outcomes has rarely been reported in the orthopaedic literature, although this process is commonly used and reported in clinical trials of other medical disciplines. Adjudication of outcomes provides more reliable and valid outcome assessment, especially when the outcome is subjective as in the case of fracture-healing. The successful implementation of adjudication in a clinical trial is an important and complex process. The process requires a substantial infrastructure of research personnel to oversee data collection at the clinical sites. The development of an adjudication charter specific to the study is a critical aspect of adjudication as it outlines the adjudication committee membership as well as their roles and responsibilities and defines the adjudication process and the decision rules. Web-based adjudication has facilitated the process as it allows rapid, efficient, and timely adjudication. This article provides an overview of the adjudication process, along with details on the common pearls and pitfalls associated with this method of outcomes assessment.

Screw augmentation in displaced femoral neck fractures. Clinical and histological results using a new composite

We wanted to assess a new technique for augmentation of parallel screws in internal fixation of displaced femoral neck fractures with a bis-GMA-based composite delivered around the screw head. Twenty-one consecutive patients admitted with displaced femoral neck fractures were operated with internal fixation with two parallel Olmed screws augmented with the composite, and followed for 24 months. The composite was introduced through the lumen of the cannulated screws and deposited in the femoral head around the threaded part of the screws. The procedure of augmenting was technically feasible and operation time was on average 33 min. Eleven patients were re-operated due to healing complications within 24 months. There were five redisplacements, four non-unions and two cases of avascular necrosis. Histological examination of four extracted femoral heads showed fragmentation of the composite into small particles with foreign-body response with giant cells and macrophages along with granulation tissue formation and low grade inflammation. The method of augmentation was technically easy, but the failure rate was high and the fragmentation of the composite with inflammatory response found on histology is noteworthy.