The short-term outcomes of cementless collared triple-tapered stem for primary total hip arthroplasty in patients ≥70-years old.

Background: Periprosthetic fractures and mechanical failure following total hip arthroplasty (THA) are not uncommon occurrences in elderly patients, especially with the use of cementless implants. The utilization of collared, triple-tapered femoral stems has demonstrated good clinical outcomes and results comparable to other femoral stems. There remains a paucity of literature on the use of these stems in older patients. In this study, we evaluated post-operative outcomes following primary THA in patients ≥70-years old using a collared, triple-tapered femoral stem. Methods: Retrospective study including 91 primary THAs in patients ≥70-years old using a triple-tapered femoral stem, between September 2017 and July 2024. Primary outcomes included intraoperative or post-operative periprosthetic fractures and subsidence of the femoral stem. Subsidence was measured on x-rays as the distance between the most proximal aspect of the greater trochanter and the shoulder of the femoral stem. Results: A total of 91 patients were included, with no periprosthetic fractures observed intraoperatively or post-operatively. The average femoral stem subsidence at 6-weeks post-operative was 1.1 mm (std dev, 0.9) compared to baseline post-operative imaging. At that time point three patients had subsidence ≥3 mm, with no clinically significant symptoms. There was one prosthetic joint infection requiring revision and three superficial surgical site infections. The overall average follow-up time was 12.5 months (std dev, 12.7). Conclusion: In this study, we found low rates of subsidence and no periprosthetic fractures following primary THA with triple-taper stems in patients ≥70-years old. Of note, no revision surgeries were performed for mechanical failure.