Increased failure rates after the introduction of the TFNA proximal femoral nail for trochanteric fractures: implant related or learning curve effect?

Abstract

Background and purpose — Trochanteric fractures are often treated using intramedullary fixation. In our institu-tion, the TFN-Advanced Proximal Femoral Nailing System (TFNA) was introduced as replacement for the Gamma Tro-chanteric Nail (GTN3) for the treatment of these fractures as a result of a hospital-driven change of trauma implant sup-plier. We compared trochanteric fracture fixation failure rate between these 2 intramedullary nails. Patients and methods — All trochanteric fractures treated surgically from 2011 to 2019 were retrospectively reviewed for fixation failure. From 2016 only the TFNA was used. Fixation failure was defined as implant cut-out, implant breakage, non-union, malpositioning of the screw/ blade requiring reoperation, new fracture around the nail, or miscellaneous. Propensity score matching was used to balance distribution of covariates and to compare failure rates between TFNA and GTN3 groups. Learning curve analyses were performed. Results — After exclusion, 797 GTN3s (779 patients) and 542 (536 patients) TFNAs were available for analysis. A higher risk of fixation failure was found in the TFNA group (14%) compared with the GTN3 group (7.0%) (hazard ratio [HR] 2.0, 95% confidence interval [CI] 1.2–3.5). This was mainly attributed to a higher risk of cut-out (HR 2.2; CI 0.9– 5.7), malpositioning (HR 4.7; CI 0.7–34), and new fracture around the nail (HR 4.0; CI 1.0–16). Learning curve analyses indicated no clear learning curve effect. Interpretation — Failure of fixation increased after a switch from the GTN3 to the TFNA proximal femoral nail for the treatment of trochanteric fractures. Cut-out and mal-positioning of the calcar screw or blade appeared to be the most dominant failure mechanisms. Modifications in implant design may have played a role in this increased risk of failure of fixation. In our institution a new implant device was intro- duced without solid clinical evidence behind it. This study may help to underline the need for medical doctors with a critical and scientific background to be involved in implant choices.