Early Periprosthetic Femoral Fractures and Stem Subsidence After Direct Anterior Total Hip Arthroplasty Using a Collared, Fully Hydroxyapatite-Coated Stem

Abstract

Early postoperative periprosthetic femoral fractures (PPFs) are serious complications after total hip arthroplasty (THA) that often require revision surgery. Although collared, fully hydroxyapatite-coated cementless stems have shown favorable clinical outcomes, limited data are available on the incidence of PPFs and stem subsidence after direct anterior approach THA using this stem design. Early fracture behavior and stem subsidence patterns in this setting remain clinically important. We investigated the incidence and clinical course of early postoperative PPF and stem subsidence after direct anterior approach THA using the UNIVERSIA stem. We retrospectively reviewed 4,094 hips that underwent primary cementless THA between September 2020 and May 2024. PPFs within 1 year were stratified by the presence or absence of trauma. Stem subsidence ≥2 mm was assessed radiographically. PPFs occurred in 16 hips (0.39%): eight non-traumatic fractures (0.20%) and eight traumatic fractures (0.20%). All non-traumatic fractures were successfully managed conservatively, whereas seven traumatic fractures (0.17%) required surgery. Stem subsidence ≥2 mm occurred in six hips (0.15%); one traumatic case required revision, and the remaining five stabilized within 3 weeks without further progression. Early PPF and stem subsidence rates were low. Stratification by trauma mechanism may help identify fractures requiring surgery, whereas non-traumatic fractures and most subsidence cases were successfully managed non-operatively. Case series; Level IV.