Proximal Implant Breakage After Cephalomedullary Nailing of Extracapsular Proximal Femur Fractures: A Multicenter Retrospective Comparative Analysis.

OBJECTIVE

To compare rates of nail breakage of 3 common cephalomedullary nails for the treatment of AO/OTA 31A1-3 femur fractures.

DESIGN

Multicenter retrospective study.

SETTING

Thirteen level I trauma centers.

PATIENT SELECTION CRITERIA: Adult patients with AO/OTA 31A1-3 femur fractures treated between 2014 and 2021 with the trochanteric fixation nail-advanced (TFNA), Gamma3, or Trigen InterTAN were included.

OUTCOME MEASUREMENTS AND COMPARISONS: The primary outcome was implant (nail or head element) breakage. The secondary outcomes included nonunion, cut-out/cut-through, and overall reoperation rate. Univariate and multivariable analyses were performed to compare breakage rates between implants while controlling for age, sex, AO/OTA 31A1-2 versus 31A3 fracture patterns, low- versus high-energy mechanisms, and postoperative neck shaft angle (NSA).

RESULTS

In total, 2130 patients were included: 770 (36.2%) TFNA, 1073 (50.4%) Gamma3, and 287 (13.5%) InterTAN. The InterTAN group had younger patients (median age: InterTan: 74, TFNA: 77, Gamma3: 80, P < 0.001), more high-energy mechanisms (InterTan: 23%, TFNA: 14%, Gamma3: 10%, P = 0.001), and more varus malreductions (NSA < 128.5: InterTan: 46%, Gamma3: 39%, TFNA: 34%, P = 0.001). The TFNA group was more likely to have an AO/OTA 31A3 fracture pattern than the Gamma3 (TFNA: 17.3%, InterTAN: 14.3%, Gamma3: 12.1%, P = 0.002). The overall rate of implant breakage was 1.4% in the InterTAN group, 1.2% in the TFNA group, and 0% in the Gamma3 group. All breakages occurred in the presence of a nonunion or delayed union. Only two of the 31A3 fracture patterns resulted in breakage, both in the TFNA group, while the remainder occurred in 31A1-2 fracture patterns ( P = 1.0). After controlling for confounding factors listed above, the TFNA and InterTAN groups were associated with a marginally increased odds of implant breakage compared with the Gamma3 (TFNA vs. Gamma3: OR: 0.04, 95% CI: <0.01-0.5, P = 0.034; InterTAN vs. Gamma3: OR: 0.04, 95% CI: <0.01-0.5, P = 0.037), while there was no difference between the TFNA and InterTAN ( P = 0.991). Postoperative NSA was not independently predictive of breakage ( P = 0.55).

CONCLUSIONS

This study suggests that the TFNA may be slightly more prone to breakage than the Gamma3 when used for extracapsular proximal femur fractures. However, breakage is a rare event after cephalomedullary nailing with all implants evaluated and is always associated with nonunion or delayed union, and the magnitude of this difference may not be clinically relevant.

LEVEL OF EVIDENCE: Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.