Comparison of Early Fatigue Failure of the TFNa and Gamma 3 Cephalomedullary Nails in the United States From 2015 to 2019

Assessing the Reproducibility of Research Based on the Food and Drug Administration Manufacturer and User Facility Device Experience Data

OBJECTIVE

This article aims to assess the reproducibility of Manufacturer and User Facility Device Experience (MAUDE) data-driven studies by analyzing the data queries used in their research processes.

METHODS

Studies using MAUDE data were sourced from PubMed by searching for "MAUDE" or "Manufacturer and User Facility Device Experience" in titles or abstracts. We manually chose articles with executable queries. The reproducibility of each query was assessed by replicating it in the MAUDE Application Programming Interface. The reproducibility of a query is determined by a reproducibility coefficient that ranges from 0.95 to 1.05. This coefficient is calculated by comparing the number of medical device reports (MDRs) returned by the reproduced queries to the number of reported MDRs in the original studies. We also computed the reproducibility ratio, which is the fraction of reproducible queries in subgroups divided by the query complexity, the device category, and the presence of a data processing flow.

RESULTS

As of August 8, 2022, we identified 523 articles from which 336 contained queries, and 60 of these were executable. Among these, 14 queries were reproducible. Queries using a single field like product code, product class, or brand name showed higher reproducibility (50%, 33.3%, 31.3%) compared with other fields (8.3%, P = 0.037). Single-category device queries exhibited a higher reproducibility ratio than multicategory ones, but without statistical significance (27.1% versus 8.3%, P = 0.321). Studies including a data processing flow had a higher reproducibility ratio than those without, although this difference was not statistically significant (42.9% versus 17.4%, P = 0.107).

CONCLUSIONS

Our findings indicate that the reproducibility of queries in MAUDE data-driven studies is limited. Enhancing this requires the development of more effective MAUDE data query strategies and improved application programming interfaces.

Total Hip Arthroplasty After Proximal Femoral Nailing: Preoperative Preparation and Intraoperative Surgical Techniques

The combination of an aging population and increased utilization of total hip arthroplasty (THA) is leading to a higher incidence of conversion THA, defined as conversion from previous hip fracture surgery to THA. Conversion THA is a more technically challenging, time-consuming, and costly procedure compared to primary THA and frequently involve more medically complex patients. Thus, the aim of this review is to provide a rubric for surgeons to use when preparing for a conversion THA. We have assessed the compatibility of commonly available extraction devices with popular femoral nails. Furthermore, we review technical pearls for conversion THA including equipment planning, operative setup, intraoperative imaging, extraction sequencing, and troubleshooting commonly encountered obstacles.

A novel intramedullary nail design of intertrochanteric fracture fixation improved by proximal femoral nail antirotation

A proper and reliable fracture fixation is important for fracture healing. The proximal femoral intramedullary nail (IN), such as proximal femoral nail anti-rotation (PFNA) or Gamma nail, is widely used for intertrochanteric fracture fixation. However, it still suffers considerable stress concentrations, especially at the junction between the nail and the blade or lag screw. In this study, we propose a novel intramedullary nail design to enhance the intramedullary nail integrity by introducing a bolt screw to form a stable triangular structure composed of the nail, the lag screw, and the bolt screw (PFTN, Proximal femoral triangle nail). Systematic finite element numerical simulations were carried out to compare the biomechanical performances of PFTN and PFNA under both static and dynamic loads during the postures of ascending and descending stairs. The simulation results highlight the advantages of the proposed PFTN design with lower stresses, less stress concentration, and higher structure stability.

Pertrochanteric Nonunion: When and Why to Consider a Medullary Implant

SUMMARY

Pertrochanteric nonunion management is a technically challenging problem. When repair is undertaken rather than conversion arthroplasty, successful treatment revolves around accurate deformity correction, preservation of vascularity, and stable durable fixation. The decision to use an extramedullary or intramedullary implant should be influenced by nonunion-specific characteristics and patient-related conditions. Failure to understand these nuances when selecting an implant strategy often results in treatment failure. The primary purpose of this article was to discuss these variables and delineate when an intramedullary implant should be considered for treatment of a pertrochanteric nonunion. The secondary purpose was to describe the author's preferred surgical technique for implant-driven deformity correction and compression when choosing an intramedullary nail.

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.

History and Evolution of Hip Design to Decrease Failure

SUMMARY

The evolution of fracture fixation designs over the past 100 years is coupled with incredible advances in materials and manufacturing technology. Failures are unavoidable and should be evaluated from the perspective of refining our technology and technique to improve patient outcomes. Failure after intramedullary fixation of hip fractures is multifactorial with contributions from an unsuccessful surgery, some preventable, some unavoidable, and rarely, design and manufacturing errors. However, whenever implants are disseminated to large population groups with variable individual anatomy, physiology, and associated comorbidities, unexpected and unpredicted weaknesses in the design and surgical technique will be discovered. Surgeons have multiple choices for nail selection with specific and critical technical requirements. The surgeon should evaluate each patient individually and determine the treatment based on patient anatomy and morphology of the fracture. The surgical approach should be modified over time after deciding how best to improve surgical treatment based on the current scientific studies.

Trust But Verify: Design Differences in The Prevention of Targeting Errors in Cephalomedullary Nails

OBJECTIVES

To evaluate insertional damage on explanted cephalomedullary nails and to differentiate typical from atypical wear to characterize outliers.

DESIGN

Therapeutic.

SETTING

Level II trauma center.

PARTICIPANTS

Patients who underwent removal of an implanted cephalomedullary nail for any reason from 2015 to 2023.

METHODS

Inspection of implants was performed at ×1000 magnification with a light microscope. Benchtop testing was performed with Gamma3, Gamma4, Intertan, TFN, and TFNa instrumentation.

RESULTS

One hundred nine cephalomedullary nails were inspected. Insertional damage was observed in more than 95% of the implants recovered. In 34% (37 of 109) of implants, damage to the proximal aperture was severe enough to cause a chamfer or "notch." Chamfers were also encountered along the distal locking aperture in short stem implants in 44% (19 of 43). Guidewire chamfers to the proximal implant external to the aperture and damage to preinserted set screws were outliers. Evidence of set screw fracture or deformity was encountered in 12 specimens. Four anomalous set screw variants were encountered within 1 implant design, each variant exhibiting maltracking with deployment that could result in malfunction.

CONCLUSIONS

Insertional damage to cephalomedullary implants was encountered routinely among the explants and should not always be categorized as preventable surgical error. Surgeons should be familiar with technical and design factors that contribute to chamfering of implants to reduce failures.

LEVEL OF EVIDENCE

Therapeutic, Level III.

Mechanical Complications After Intramedullary Fixation of Extracapsular Hip Fractures

Extracapsular hip fractures occur frequently in the elderly as a result of low-energy trauma. Achieving stable fixation in osteoporotic bone to allow early weight bearing is a key objective in the treatment of these injuries. Many of the intraoperative decisions facing surgeons are directed by first determining fracture stability. Unstable fracture patterns should be fixated with intramedullary nails, aiming to control motion around the implant and at the fracture site. Torsion control devices provide additional stability and control, although their exact indications are not precisely defined. Complications that arise as a result of the early loading can be avoided with a good surgical reduction, meticulous technique, and proper implant selection. Mechanical complications include cutout, inordinate proximal femoral shortening, delayed union, early implant fracture, nail toggle, and cut through/medial migration.

Conversion total hip arthroplasty for early failure following unstable intertrochanteric hip fracture: what can patients expect?

PURPOSE

To report surgical outcomes in patients treated with conversion total hip arthroplasty (CTHA) for early failure of cephalomedullary nails (CMNs).

METHODS

A retrospective review was conducted of CTHA for treatment of failed CMN within 1 year of initial surgery for intertrochanteric (IT) hip fractures. The cohort was matched 1:5 to patients who underwent elective primary THA (PTHA). Patient demographics, mechanism of CMN failure, surgical outcomes, and complication rates were assessed.

RESULTS

22 patients met criteria with a mean time to failure of 145 days. Modes of failure included: lag screw cut-out with superior migration (9, 40.9%), or medialization (8, 36.4%), and aseptic nonunion with implant failure (2, 9.0%) and without implant failure (3, 13.6%). Fourteen of the patients (63.6%) had acetabular-sided damage secondary to lag screw penetration, all in the screw cut-out groups. Patient demographics were similar between cohorts. Compared to PTHA, CTHA patients had increased operative time, blood loss, LOS, and readmission rates. After IMN failure, the operative leg was shorter than the contralateral leg in all cases. CTHA restored leg lengths to <  = 10 mm in 15 (68.1%) of patients, with an average leg length discrepancy after CTHA of 6.7 mm. CTHA patients had increased rates of overall surgical complications and medical complications, specifically anemia (all p < 0.01). Tranexamic acid was used less often in the CTHA group (p < 0.01). Rate of periprosthetic joint infection (PJI), dislocation, and revision were all higher in the CTHA, though did not reach statistical significance.

CONCLUSION

The majority (77.3%) of CMN implant failure for nonunion within 1 year was due to screw cut-out. CTHA is a salvage option for early failed IT hip fracture repair, but expected surgical outcomes are more similar to revision THA than primary THA, with increased risk of readmission, longer surgery and LOS, increased blood loss, and higher complication rates.

LEVEL OF EVIDENCE

III, Retrospective comparative study.

Risk of Revision After Hip Fracture Fixation Using DePuy Synthes Trochanteric Fixation Nail or Trochanteric Fixation Nail Advanced: A Cohort Study of 7,979 Patients

BACKGROUND

Prior reports of the DePuy Synthes Trochanteric Fixation Nail Advanced (TFNA) revealed a potential mode of fatigue failure at the proximal screw aperture following fixation of extracapsular hip fractures. We sought to compare the revision risk between the TFNA and its prior-generation forebear, the Trochanteric Fixation Nail (TFN).

METHODS

A retrospective cohort study was performed using data from a U.S. integrated health-care system's hip fracture registry. The study sample comprised patients who underwent cephalomedullary nail fixation for hip fracture with a TFN (n = 4,007) or TFNA (n = 3,972) from 2014 to 2019. We evaluated the charts and radiographs for patients who underwent any revision. Multivariable Cox regression was used to evaluate the risk of revision related to the index fracture.

RESULTS

At the 3-year follow-up, the cumulative probability of revision related to the index fracture was 1.8% for the TFN and 1.9% for the TFNA. After adjustment for covariates, no difference was observed in revision risk (hazard ratio [HR], 1.18 [95% confidence interval (CI), 0.80 to 1.75]; p = 0.40) for the TFNA compared with the TFN. The TFNA was associated with a higher risk of revision for nonunion than the TFN (HR, 1.86 [95% CI, 1.11 to 3.12]; p = 0.018). At the 3-year follow-up, implant breakage was 0.06% for the TFN and 0.2% for the TFNA; with regard to aperture failures related to the index fracture, there were 1 failure for the TFN group and 3 failures for the TFNA group.

CONCLUSIONS

In a large cohort from a U.S. hip fracture registry, the TFNA had an overall revision rate that was similar to that of the earlier TFN, with implant breakage being a rare revision reason for both groups. Chart and radiographic review found that the TFNA was associated with a higher risk of revision for nonunion.

LEVEL OF EVIDENCE

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

Case report: unique failure of a Synthes TFNA fenestrated lag screw in a peritrochanteric nonunion

Background:

Intertrochanteric femur fractures are a common orthopaedic injury that are often treated surgically. Cephalomedullary nails (CMN) are frequently the implant of choice for intertrochanteric femur fractures, resulting in low complication rates. Implant failure is a rare but reported complication. Common locations of failure include the proximal nail aperture, distal screw holes, and implant shaft. In this case report, we describe a CMN failure pattern through fenestrated cephalic screw holes.

Case:

A 70-year-old female sustained an OTA 31A-2.2 peritrochanteric fracture during a motor vehicle collision. She was treated the following day with a Synthes Trochanteric Fixation Nail—Advanced CMN utilizing a fenestrated cephalic screw. There were no intraoperative complications. She was made non-weight bearing for 8 weeks after the procedure due to ipsilateral foot fractures. At 6 months follow-up she was noted to have a delayed union. 11 months postoperatively she suffered a ground level fall and the cephalic lag screw failed through its fenestrations, resulting in varus collapse of her fracture at the femoral neck. The patient then underwent nail extraction and salvage total hip arthroplasty.

Conclusion:

Cephalomedullary nail implant failure is presented with implant fracture propagation through a fenestrated cephalic screw. Cephalomedullary lag screw failure is rare and can be difficult to manage. It is important to monitor new implants for unique failure mechanisms.

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

Is there a role for cementless primary stem in hip arthroplasty for early or late fixation failures of intertrochanteric fractures?

Background

The choice of femur stems during the hip arthroplasty procedures for patients with treatment failure of intertrochanteric fractures (ITF) remains controversial. We aimed to compare the surgical complication and reoperation rates between cementless primary and revision stems in the early (≤3 months) and late (> 3 months) fixation failures of ITF.

Methods

This was a retrospective, cohort study conducted in a single, tertiary referral hospital of Taipei, Taiwan. We included hip arthroplasty procedures for failed ITF using cementless primary or revision stems. There were 40 and 35 patients who had early and late fixation failure of ITF, respectively. The patient demographics, time to fixation failure, surgical complications and medical complications were recorded for analysis.

Results

We included 75 patients that underwent hip arthroplasty procedure for failed ITF using cementless primary (n = 38) or revision (n = 37) stems. The mean age was 79.3 years and 56% of the patients were female. In the early fixation failure group, the complication rate was similar between the primary and revision stems (44% vs. 29%, p = 0.343). However, there was a trend toward a higher reoperation rate (31% vs. 8%, p = 0.061) of using the primary stem, compared with the revision stem. In the late fixation failure group, the rate of complication and reoperation was similar between the two stem types.

Conclusion

For early fixation failures of ITFs, we caution against the use of cementless primary stems due to a trend towards an increased risk of reoperations compared to the use of cementless revision stems. However, in late fixation failures of ITFs, there is a role for cementless primary stems.

Level of evidence

III, retrospective cohort study.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12891-022-05223-x.

Implant fracture of the TFNA femoral nail

BACKGROUND

The TFNA (Trochanteric Fixation Nail Advanced) Proximal Femoral Nailing System (DePuy Synthes) is frequently used for intramedullary fixation of proximal femoral fractures. The aim of this study was to evaluate all TFNA implant fractures at a UK trauma unit to ascertain any patient or surgical factors associated with implant failure.

METHODS

A retrospective study was carried out identifying all patients that sustained a TFNA implant fracture over a five-year period. Data was collected on demographic information, ASA, co-morbidities, mechanism of injury, fracture pattern according to the AO/OTA classification, procedure details and time to failure. Radiographs were assessed by two independent reviewers to identify tip-apex distance (TAD), calcar TAD, reduction quality and union status at time of implant failure.

RESULTS

Six cases were identified, all with implant breakage at the aperture for the proximal screw. All femoral fractures were intertrochanteric reverse obliquity type (OA/OTA 31A3). Two were traumatic fragility fractures and the remainder atraumatic. Mean time from index surgery to revision was 441 days (104-963). Mean TAD was 20.5 mm (15-24) and mean calcar TAD 24 mm (18-32). All six cases displayed radiographic non-union at the time of implant fracture.

CONCLUSION

Pathological fractures resulting in reverse obliquity type fracture patterns and subsequent non-union appear to be contributory factors to TFNA breakage at the proximal screw aperture. This may be further exacerbated by alterations to the nail design from previous generations. In these patients, close follow up with clinical and radiographic surveillance should be employed. Further biomechanical and clinical studies are required to compare this finding against other nail designs.

Bent or broken: analysis of set screw fracture in the TFNa implant

Objectives

To evaluate set screw fracture in the Trochanteric Femoral Nail Advanced implant (TFNa, Synthes, West Chester, PA) and to identify additional mechanisms of set screw failure in the TFNa.

Materials and methods

Patients who had experienced failure after open reduction and internal fixation (ORIF) with the TFNa were identified. TFNa implants were explanted and inspected following revision surgery. Medical device reports (MDRs) and manufacturer’s inspection reports describing similar failures for the TFNa in the United States Food and Drug Administration (FDA) Manufacturer and User Facility Device Experience (MAUDE) database were also reviewed.

Results

Four set screw fractures that occurred at a level II trauma center were observed. Sixty-seven reported failures were identified in the MAUDE database for review. Twenty-eight failed implants were returned to the manufacturer for inspection with a published inspection report available for analysis. Set screw fractures can occur in the TFNa when the set screw is deployed prematurely into the proximal screw aperture prior to blade/screw insertion. The set screw can also bend and deform if it is advanced against a helical blade/lag screw that is not fully seated into position, thereby potentially compromising its function.

Conclusion

The TFNa set screw allows for potential fracture during implant insertion leading to uncontrolled collapse, early excessive proximal femoral shortening, and rotational instability of the helical blade/lag screw. Similar failures in the TFNa can be prevented by having the surgeon inspect the proximal screw aperture after attachment of the proximal aiming aim to ensure the set screw has not been deployed prematurely.

Level of evidence

Therapeutic Level III.

Supplementary Information

The online version contains supplementary material available at 10.1186/s10195-021-00594-8.

Finite Element Analysis of Fracture Fixation

PURPOSE OF REVIEW

Fracture fixation aims to provide stability and promote healing, but remains challenging in unstable and osteoporotic fractures with increased risk of construct failure and nonunion. The first part of this article reviews the clinical motivation behind finite element analysis of fracture fixation, its strengths and weaknesses, how models are developed and validated, and how outputs are typically interpreted. The second part reviews recent modeling studies of the femur and proximal humerus, areas with particular relevance to fragility fractures.

RECENT FINDINGS

There is some consensus in the literature around how certain modeling aspects are pragmatically formulated, including bone and implant geometries, meshing, material properties, interactions, and loads and boundary conditions. Studies most often focus on predicted implant stress, bone strain surrounding screws, or interfragmentary displacements. However, most models are not rigorously validated. With refined modeling methods, improved validation efforts, and large-scale systematic analyses, finite element analysis is poised to advance the understanding of fracture fixation failure, enable optimization of implant designs, and improve surgical guidance.