Collared, Uncemented Stems Markedly Reduce Periprosthetic Femoral Fracture Risk in Women ≥ 70 Years: A Swiss National Registry Study.
TL;DR
In women aged ≥ 70 years, uncemented THA was associated with a higher risk of PFF revision compared with cemented fixation, and collared cementless stems may represent a safe uncemented alternative to cemented stem fixation.
Abstract
INTRODUCTION Uncemented total hip arthroplasty (THA) is associated with an increased risk of periprosthetic femoral fractures (PFF) in elderly women, yet its use continues to expand in this high-risk population. Stem design, particularly the presence of a collar, may influence the risk. However, sex-specific, large-scale registry data addressing this question remain limited. This study evaluated the association between stem design, design variants, and PFF risk in women aged ≥ 70 years undergoing uncemented THA.
Methods
Data were obtained from the Swiss National Joint Registry (SIRIS). Women aged ≥ 70 years who underwent uncemented THA for osteoarthritis between 2012 and 2024 were included. There were nine cementless stem models with greater than 1,000 implantations each that were analyzed by design variant (collared versus collarless, standard versus high offset, varying neck-shaft angles (NSA), and relative stem length). A total of 32,874 patients were included (mean age 76 years, mean body mass index (BMI) 26.5). The THAs with cemented stem fixation served as a reference population. The primary outcome was revision for PFF; multivariable logistic regressions were used to adjust for patient- and implant-related factors.
Results
The overall PFF revision rate was 0.5%, compared with 0.2% in the older, more medically vulnerable cemented group (P < 0.001). The PFF incidence varied substantially across uncemented stems (0.1 to 1.1%). Collared stems had a significantly lower PFF risk than collarless variants (0.1 versus 0.6%; adjusted odds ratio: 0.08, 95% confidence interval: 0.03 to 0.27, P < 0.001). Offset, neck-shaft angle, and relative stem length were not associated with fracture risk.
Conclusion
In women aged ≥ 70 years, uncemented THA was associated with a higher risk of PFF revision compared with cemented fixation. Within cementless designs, the presence of a collar was strongly associated with a reduced risk of PFF, whereas other design variants were not. These findings suggest that in elderly women, collared cementless stems may represent a safe uncemented alternative to cemented stem fixation.