BACKGROUND
Proximal femoral fractures are often treated with cephalomedullary nails. Although nail breakages following fracture repair are infrequent, a recent implant retrieval study suggested that the TFN-ADVANCED (TFNA) Proximal Femoral Nailing System (DePuy Synthes) was susceptible to post-implant breakage. It is unclear whether the risk of breakage among patients who receive the TFNA implant is higher than patients who receive other comparable cephalomedullary nails. The current study was designed to evaluate the comparative risk of breakage of the TFNA nail.
METHODS
Using data from a large U.S. health-care database, the current study was designed to determine whether TFNA nails have equal, lower, or higher risk of breakage relative to all other comparable, single-head-element (with no additional lag screws), cephalomedullary nails, the Stryker Gamma3 and the Zimmer Natural Nail, referred to in this study as the non-TFNA group. Data were from patients who received the TFNA implant or non-TFNA nails in 365 hospitals between February 1, 2014, and September 30, 2019. Analysis of nail breakage post-implantation was prespecified as the difference between the TFNA group and the non-TFNA group in cumulative incidence at 18 months, with a prespecified equivalence margin of 0.5%, using data balanced on measured covariates by propensity score weighting.
RESULTS
Within the first 18 months of implantation, in 14,370 patients with TFNA nails, there were 27 nail breakages, and in 8,260 patients with non-TFNA nails, there were 29 nail breakages. The mean time to nail breakage was 4.72 months for the TFNA group and 4.05 months for the non-TFNA group. In the balanced data, the risk of breakage at 18 months was 0.26% (95% confidence interval [CI], 0.17% to 0.36%) for the TFNA group and 0.25% (95% CI, 0.05% to 0.45%) for the non-TFNA group, with a risk difference of 0.01% (95% CI, -0.21% to 0.24%). This result indicates that the cumulative incidence of nail breakage was equivalent (between -0.5% and 0.5%) for both nail groups. The risk differences were also within the equivalence margin in subgroup analyses: pertrochanteric fractures only (-0.08% [95% CI, -0.34% to 0.19%]), pertrochanteric or subtrochanteric fractures (-0.04% [95% CI, -0.29% to 0.21%]), and those with International Classification of Diseases, Tenth Revision (ICD-10) data only (0.03% [95% CI, -0.18% to 0.25%]).
CONCLUSIONS
The risk of nail breakage was equivalent for TFNA and comparator cephalomedullary nails.
LEVEL OF EVIDENCE
Therapeutic Level III. See Instructions for Authors for a complete description of levels of evidence.