High risks of failure observed for A1 trochanteric femoral fractures treated with a DHS compared to the PFNA in a prospective observational cohort study

INTRODUCTION: Both the DHS and the PFNA are common and well-studied treatment options for stable trochanteric fractures. The aim of the current study was to compare the implant failure rates of these two implants in 31A1 type trochanteric femoral fractures. MATERIALS AND METHODS: A single-centre observational cohort study was conducted in the Hip Fracture Unit of a multicentre level 1 trauma teaching hospital between December 2016 and October 2018. Patients with an AO/OTA type 31A1 fracture were included. Pathological fractures, bilateral fractures, high-energy traumas and patients younger than 18 years of age were excluded. Surgery was performed using either a DHS or PFNA. Both were used routinely for stable trochanteric fractures, and allocation was decided by the surgeon performing the operation. The primary outcome of this study was the implant failure rate in the first postoperative year. Secondary outcomes included the reoperation rate, functional recovery, pain and morphine use. RESULTS: Data were available from 126 patients treated with a DHS (n = 32, 25.4%) or PFNA (n = 95, 74.6%). Minor differences were observed in the patient characteristics including the prevalence of cognitive impairment (18.8% vs 40.2%; P = 0.028), prefracture independence in activities of daily living (87.1% vs 67.4%; P = 0.034) and prefracture mobility (independently without aides: 61.3% vs 40.4%; P = 0.033). Fractures treated with a DHS showed 25% implant failures, compared to 1.1% for fractures treated with a PFNA (P = 0.004). No differences were observed in any of the secondary outcomes. CONCLUSIONS: Significantly more implant failures were observed for the DHS compared the PFNA within 1 year after surgery. Despite the fact that this did not result in differences in revision surgery, we conclude that the PFNA, considering the minimal number of implant-related fractures is a viable implant for A1 type trochanteric fractures. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s00402-021-03824-0.