Collared stems are protective against revision due to early periprosthetic femoral fracture: A cross-sectional study.

Abstract

Collared stems have demonstrated acceptable long-term survivorship in cementless total hip arthroplasty (THA). However, their impact on early postoperative periprosthetic femoral fracture (PFF) remains unclear. This study compares early PFF rates requiring revision between collared and collarless stems in cementless THA and identifies risk factors. All consecutive patients undergoing primary, navigated, cementless unilateral THAs at our center from 2018 to 2024 were included. Non-navigated, cemented, or revision THAs were excluded. Early PFFs, defined as fractures within 90 days, were classified using the Vancouver system. Among 2859 patients (mean age 63.79 ± 10.58), 64.4 % received collarless stems. They were significantly younger (60.92 ± 10.49 vs. 68.99 ± 8.57, <i>p</i> < 0.001). Most in the collared group were female (62.7 %), while collarless recipients were mainly male (55.1 %, p < 0.001). Patients with ASA ≥3 were more likely to receive collared stems (72.6 % vs. 37.0 %, <i>p</i> < 0.001). Fifteen PFFs requiring revision were identified, all Vancouver B2, with 86.6 % classified as early PFFs. The fracture rates were comparable in univariate analysis (<i>p</i> = 0.128). Regression analysis showed collared stems significantly reduced PFF risk (OR: 0.081, 95 % CI: 0.01-0.39, <i>p</i> = 0.001). Conversely, increasing age (OR: 1.157 per year, 95 % CI: 1.07-1.27, <i>p</i> < 0.001) was associated with higher risk. Collared stems significantly reduced PFF risk after adjusting for confounders, while older age independently increased fracture risk. Therefore, careful patient selection is crucial, especially for older patients.