Comparison of the RFN-advanced femoral nailing system versus locked lateral plating in the management of distal femur fractures: A matched-cohort analysis

Abstract

Introduction: Distal femur fractures are commonly managed with retrograde femoral nailing or locked lateral plating (LLP). As implant design has evolved, more distal and complex patterns are being treated with intramedullary implants. The aim of the present study was to compare early outcomes in distal femur fractures managed with the novel DePuy Synthes RFN-Advanced (RFNA) Retrograde Femoral Nailing System to a similar cohort treated with locked lateral plating.

Patients and methods: This is a retrospective cohort study of operative distal femur fractures that presented to our Level I trauma center over a 7-year period. We included patients with AO/OTA types 33A2-3, 33C1-2 fractures treated with either the RFNA or a lateral locked plate over two distinct time points. Injury radiographs were reviewed independently by three orthopedic traumatologists to include only cases deemed "nailable." Primary outcomes included coronal and sagittal alignment. Secondary outcomes included nonunion, surgical site infection (SSI), and unplanned reoperation.

Results: We identified 107 patients treated with either the RFNA (n = 45) or LLP (n = 62) over the 7-year study period. No significant differences were identified in the rates of sagittal (2.2 % versus 9.7 %, P = 0.12) or coronal malalignment (2.2 % versus 0 %, P = 0.421). The nonunion rate was 8.9 % in the RFNA cohort versus 19.4 % in the LLP cohort, but this difference was not statistically significant (P = 0.174). We also found no difference in infection or implant failure between groups. Screw backout occurred in 8 RFNA patients (17.8 %), with 7 patients undergoing screw removal (15.6 %) either in clinic (n = 5) or the operating room (n = 2).

Discussion and conclusions: This matched cohort study demonstrated promising results comparing the RFNA to lateral plating of distal femur fractures. The nonunion rate of 9 % in the RFNA cohort adds to recent literature that supports improved union rates with intramedullary nailing of these fractures. Interlocking screw backout was the most common complication with RFNA treatment at a rate of 16 %, with the majority removed in clinic.

Level of evidence: Level III.

Keywords: Distal femur fracture; Femoral malalignment; Femoral malunion; Femoral nonunion; Lateral plate; RFNA; Retrograde nail.