Characteristics of intramedullary nail breakage in pertrochanteric femur fractures: a summary of 70 cases

Impact of lateral cortical notching on biomechanical performance in cephalomedullary nailing for unstable pertrochanteric fractures

PURPOSE

In pertrochanteric femur fractures the risk for fracture healing complications increases with the complexity of the fracture. In addition to dynamization along the lag screw, successful fracture healing may also be facilitated by further dynamization along the shaft axis. The aim of this study was to investigate the mechanical stability of additional axial notch dynamization compared to the standard treatment in an unstable pertrochanteric femur fracture treated with cephalomedullary nailing.

METHODS

In 14 human cadaver femora, an unstable pertrochanteric fracture was stabilized with a cephalomedullary nail. Additional axial notch dynamization was enabled in half of the samples and compared against the standard treatment (n = 7). Interfragmentary motion, axial construct stiffness and load to failure were investigated in a stepwise increasing cyclic load protocol.

RESULTS

Mean load to failure (1414 ± 234 N vs. 1428 ± 149 N, p = 0.89) and mean cycles to failure (197,129 ± 45,087 vs. 191,708 ± 30,490, p = 0.81) were equivalent for axial notch dynamization and standard treatment, respectively. Initial construct stiffness was comparable for both groups (axial notch dynamization 684 [593-775] N/mm, standard treatment 618 [497-740] N/mm, p = 0.44). In six out of seven specimens the additional axial dynamization facilitated interfragmentary compression, while maintaining its mechanical stability. After initial settling of the constructs, there were no statistically significant differences between the groups for either subsidence or rotation of the femoral head fragment (p ≤ 0.30).

CONCLUSION

Axial notch dynamization provided equivalent mechanical stability compared to standard treatment in an unstable pertrochanteric fracture. Whether the interfragmentary compression generated by axial notch dynamization will promote fracture healing through improved fracture reduction needs to be evaluated clinically.

The effect of distal locking mode on postoperative mechanical complications in intertrochanteric fractures: a retrospective cohort study of five hundred and seven patients

PURPOSE

The optimal choice of distal locking modes remains a subject due to limited available data, and therefore, this study aims to investigate the relationship between distal locking mode and postoperative mechanical complications in an intertrochanteric fracture (ITF) population who underwent closed reduction and intramedullary fixation with a PFNA-II.

METHODS

Patients aged 65 years or older who underwent surgery with PFNA-II fixation in a university teaching hospital between January 2020 and December 2021 were potentially eligible. Based on the distal locking mode, patients were classified into static, dynamic, and limited dynamic groups, among which the differences were tested using univariate analysis. Multivariate logistic regression was used to examine whether the distal locking mode was independently associated with the risk of postoperative one year mechanical complications, adjusting for covariates and potential confounders. Subgroup analyses were performed to evaluate the robustness of the findings.

RESULT

Among 507 eligible patients, 33 (6.5%) developed postoperative mechanical complications. In the univariate analysis, sex (P = 0.007), fracture type (P = 0.020), LAT Parker ratio (P = 0.023), and lateral femoral (P = 0.003) wall showed that the differences were significant. Compared to the static group, the limited dynamic group and the dynamic group showed higher odds of postoperative mechanical complications (OR = 3.314, 95% CI: 1.215-9.041; and OR = 3.652, 95% CI: 1.451-9.191, respectively). These associations were robust across a series of analyses, including adjusting for confounders and subgroup analyses.

CONCLUSION

Using a distal non-static locking mode significantly increases the risk of postoperative mechanical complications, and static locking could be a preferable option when treating an intertrochanteric fracture.

Defining Cephalomedullary Nail Breakage Rates: A Systematic Review and Meta-Analysis

OBJECTIVE

To establish the background rate of breakage of cephalomedullary nails.

DATA SOURCES

MEDLINE, PubMed, and Web of Science were searched on April 3, 2023.

STUDY SELECTION

All English-language studies that examined trochanteric with or without subtrochanteric fractures and identified cephalomedullary nail breakage as an outcome measure and a breakage rate could be derived were included. Implants captured were predominantly the TFNA, TFN, and PFN by DePuy Synthes, various versions of the Gamma nail by Stryker, the Zimmer Natural Nail by Zimmer Biomet, and the Intertan by Smith and Nephew.

DATA EXTRACTION

The author, year of publication, dates of implant insertion, study design, method of detection of breakages, implant used, number of implant breakages, number of implants inserted, breakage rate, and follow-up were extracted.

DATA SYNTHESIS

Meta-analysis of included studies used descriptive nonparametric statistics and a noncomparative proportion for the pooled result. Differences in results between study design types were compared using the mean breakage rate per study design.

CONCLUSIONS

Cephalomedullary nail breakage is a rare complication with a median reported rate of 0.6% and a pooled result rate of 0.4%. Ninety-five percent of studies had a breakage rate of 1.3% or less, which sets a benchmark from the reported literature for future studies. There is wide variability in rates of breakage reported between different types of study designs with single-center review studies reporting breakage rates nearly 4-fold greater than large-scale administrative database reviews. The rate of implant breakage should not be used in isolation to judge an implant's performance.

LEVEL OF EVIDENCE

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

Use of the Heracles straight blade in the treatment of intertrochanteric hip fractures: a prospective study with a 1-year follow-up

INTRODUCTION

The treatment of intertrochanteric fractures in the elderly remains challenging for orthopedic surgeons, due to aging, comorbidities, and poor bone quality. The Heracles straight blade has proven a lower rate of cut-out and femoral head displacement in biomechanical studies; however, there are currently no published clinical studies using this nail.

PURPOSE

To analyze the clinical and radiological results of the Heracles nail with the straight cephalic Heracles blade as a device to treat osteoporotic intertrochanteric fractures of the proximal femur.

METHODS

A total of 136 patients with trochanteric hip fractures were operated on by the same surgeon, using the Heracles nail with a straight cephalic blade. However, only 86 patients completed the 1-year follow-up both clinically and radiologically. According to the Association of Osteosynthesis classification, 38 patients (44.1%) had 31-A1, 36 patients (41.6%) had 31-A2, and 12 patients (14.1%) had 31-A3. Functional outcomes were assessed according to the Katz and Barthel scores, finding that 58% of patients recovered their original functional level, According to Barthel score, a mean loss of 11.8 points was found.

RESULTS

The mean hospital stay was 8.22 days (mean preoperative stay of 2.71 days). The mean tip-apex distance was 15.2 mm. During the follow-up, 6 complications (6.96%) were detected: 4 cut-out, 1 cut-in, and 1 nail breakage. According to the Katz score, 58% of the patients recovered their previous functional status and 20.58% needed an additional walking aid. The mean loss in the Barthel score was 11.8 points.

CONCLUSION

The Heracles nail using a cephalic straight blade has proven to be a valid treatment of trochanteric fractures, due to the functional recovery of the patients and low level of complications.

Posterior Protrusion Measures (PPM) as an Innovative Index in Classifying Plain Lateral Radiograph Images of Pertrochanteric Fracture Using the Revised AO Foundation/Orthopaedic Trauma Association (AO/OTA) Classification

Introduction The absence of a precise fracture classification system that classifies pertrochanteric fractures into either stable or unstable contributes to a burden on healthcare and has several major implications. We propose an innovative graphical index, which we refer to as posterior protrusion measures (PPM), using plain lateral view radiograph images for the revised AO Foundation (Arbeitsgemeinschaft für Osteosynthesesfragen)/Orthopedic Trauma Association (AO/OTA) classification system. This study aims to: (i) introduce the use of PPM for classifying fractures into stable or unstable under the revised AO/OTA classification system and set the threshold numeric value, (ii) elucidate the reproducibility of inter and intra-observer agreement, and investigate the consistency of fracture classification using PPM versus computed tomography (CT) scan images. Materials and methods Out of 146 patients identified from the database, a total of 126 patients were enrolled in the study. Pertrochanteric fractures were classified as either stable or unstable. Three surgeons were assigned for PPM determination. Regarding the demographical data, the chi-square test was used to assess the significance of each parameter on a categorical scale between the two groups. The independent sample t-test or the Mann-Whitney U test was used to compare the two independent groups. Interclass correlation coefficient (ICC) values for continuous variables and kappa values (κ) for categorical variables were calculated to assess inter-observer and intra-observer agreement. Receiver-operating characteristic (ROC) analysis was used to determine optimal cut-off points of PPM to predict consistency between separate fracture classification groups, one using PPM values with a threshold derived from plain radiograph images, and the other using CT scan images. Results Among a total of 126 pertrochanteric fractures, the A1 (stable) group consisted of 39 patients (10 males, 29 females), whereas the A2 (unstable) group consisted of 87 patients (14 males, 73 females) (not significant, NS). Intraclass correlation coefficient (ICC) values of PPM for the inter-observer agreement were 0.796 (0.723-0.852), 0.664 (0.554-0.751), and 0.702 (0.601-0.781) at first examination and 0.729 (0.635-0.801) at the second. The intra-observer agreement was 0.869 (0.819-0.906) and 0.603 (0.480-0.703). We examined for consistency of fracture classification group of PPM values with a threshold of 0.4 (A1<0.4, A2=0.4 or more) and CT-based group. For the first examination, there was mostly "moderate" agreement in fracture classification (stable or unstable) between plain radiograph and CT scan images, κ (95%CI): 0.427 (0.266-0.588), 0.493 (0.335-0.651), and 0.359 (0.176-0.544), and for the second, 0.418 (0.251-0.585), and 0.451 (0.284-0.620), respectively. Conclusion We propose a supplementary tool, namely PPM that allows for possible alternative classification of pertrochanteric fractures into A1 (stable) and A2 (unstable) using plain radiograph images under the revised AO/OTA classification system. In this study, a PPM threshold value of 0.4 demonstrated a moderate inter- and intra-observer agreement. It is noteworthy to mention that there was a satisfactory consistency of fracture classification using PPM derived from plain radiograph images when compared to classification using CT scan images. In addition, the PPM method provides a numerical score.

Removal of a Broken Intramedullary Nail: A Case Report and Technical Description

The removal of a broken intramedullary nail is a challenging procedure. Several surgical techniques have been described to remove the distal end of the nail. Here, we report the surgical technique for removing broken Fitbone® lengthening nail using a cerclage wire. This is an effective and reproducible technique that does not require specialized equipment, the development of a cortical window, or an arthrotomy and is applicable for all types of intramedullary nails.

Tips and tricks to avoid implant failure in proximal femur fractures treated with cephalomedullary nails: a review of the literature

Objective:

To describe the surgical aspects potentially contributing to hardware failure of cephalomedullary nails.

Data Sources:

A search of the Embase, PubMed (MEDLINE), Web of Science, and the Cochrane library for reports of hardware failures after intramedullary fixation of proximal femur fractures. Issues of cut out and cut through phenomena related to technique were excluded. Expert opinion of 3 surgeons, each trained on several fixation systems at Level | trauma centers is reported.

Data Extraction:

Three authors extracted data using a predesigned form. Implant type, reported failure mechanism, and associated factors with implant failure were recorded as well as potential bias.

Results:

Of 2182 search results screened, 64 articles were deemed relevant for our research question and were included. The authors identified factors associated with implant failure: preoperative patient and fracture characteristics, intraoperative reduction, implant handling, and postoperative nonunion. Issues were identified as independent modifiable intraoperative risk factors: inadequate fracture reduction, varus position of femoral neck, direct damage of the cephalomedullary nail aperture by eccentric drilling related to guide sleeve handling, and implant design mechanism failures.

Conclusions:

Multiple factors associated with intraoperative handling can influence the healing of proximal femur fractures. Although many of these have been well described and are taught in fracture courses, surgeons should be aware of subtle intraoperative complications reported in the literature that can weaken implants and add to the likelihood of early failure.

Level of Evidence: IV

Proximal Femoral Nail Mechanical Failure: A Case Report and Biomechanical Study

Intramedullary nailing is an established method for treating pertrochanteric fractures. However, the widespread use of this technique comes along with a variety of complications. We present a case of a 50-year-old female who presented to the emergency department suffering a left pertrochanteric fracture. She was treated with proximal femoral nailing and discharged home. Nine months later, she presented again to the emergency department with pain and an inability to bear weight. Imaging revealed the mechanical failure of the hip screw and loss of fracture fixation. Revision surgery included extraction of the broken hardware and a left hip hemiarthroplasty. The removed implant was sent for further evaluation. Fractographic analysis showed acute breakage due to bending and torsion forces acting on the screw with no relevant signs of metal fatigue. This biomechanical method is of great value for the surgeon and the implant manufacturer in order to understand the failure pattern and optimize future implants and fixation techniques. Improved implant biomechanical properties together with meticulous surgical technique constitute the cornerstones for optimal results.