The Femoral Neck System versus the Dynamic Hip Screw in patients with a femoral neck fracture: 2-year follow-up of a multicenter study.

Abstract

The aim of this study was to compare clinical outcomes of the Femoral Neck System (FNS) (Depuy Synthes) and the Dynamic Hip Screw (DHS) (Depuy Synthes) in the head preserving treatment of femoral neck fractures. A multicenter retrospective study was performed in three level II trauma centers in The Netherlands. All patients younger than 90 years treated with the DHS or the FNS for a femoral neck fracture between 2012 and 2022 were included. The follow-up of the included patients was two years. The primary outcome was treatment failure, defined as avascular necrosis, non-union or implant cut-out. Secondary outcomes were postoperative infections, total hip prosthesis conversion rates and mortality. A total of 505 patients were included in this study: 239 patients with the DHS and 266 patients with the FNS. Patients treated with the FNS had a higher prevalence of Garden I type fractures and a lower prevalence of Pauwels' type III fractures. Treatment failure occurred in 77 patients, with 39 in the DHS and 38 in the FNS group. After correction for Garden and Pauwels' classification, no significant difference was noted regarding treatment failure within 2 years follow-up between both groups. No differences in conversion rates to total hip arthroplasty (coxarthrosis as surgical indication) was observed. However, patients treated with the DHS underwent implant removal more often. No differences in mortality rate between the groups was observed during two years of follow-up. This multicenter study showed that no difference in treatment failure was found between the two groups, making the FNS a viable alternative for head preserving treatment of femoral neck fractures.