Femoral Stem Design Influences Early Periprosthetic Fracture Risk Following Total Hip Arthroplasty

Background Periprosthetic femur fracture (PFF) is a significant complication following total hip arthroplasty (THA). Modern collared, triple-taper metaphyseal-filling stems may reduce fracture risk. This study compared a triple-taper metaphyseal stem with other cementless designs to assess early PFF risk, fracture risk by age and bone quality, and the impact of collar position. Methods This retrospective study analyzed 774 primary cementless THAs, including triple-taper metaphyseal (n = 311), single-wedge (n = 294), double-wedge (n = 116), and gradual taper/metadiaphyseal-filling (n = 53) stems. Triple-taper stems were implanted through a prospective multicenter trial, while comparison stems were from a single health system. Patients were stratified by stem design, age, Dorr classification, and collar position. The primary outcome was 90-day PFF. Results PFF occurred in 53 patients (6.8%), including 15 (1.9%) postoperative fractures requiring reoperation. Patients with PFF were older ( P < .001) and predominantly female ( P = .02). Triple-taper stems demonstrated lower PFF risk than other designs (odds ratio 0.20; 95% confidence interval, 0.08–0.48; P < .001). PFF rates were 1.9% for triple-taper, 7.8% for single-wedge, 14.7% for double-wedge, and 13.2% for gradual taper stems (all P < .001). Differences persisted across age groups and Dorr A/B femurs. Proud collar positioning increased PFF risk (6.3% vs 0.8%; P = .02). Conclusions Collared, triple-taper metaphyseal stems were associated with lower early PFF risk across patient ages and bone quality profiles. Seating the collar on the calcar further reduced fracture incidence.