Is the use of primary cementless stem in revision total hip arthroplasty a reliable option? A systematic review.

BACKGROUND: While revision-specific stems are standard for revision total hip arthroplasty (rTHA), cementless primary stems are an emerging alternative for patients with preserved bone stock. However, their long-term reliability remains under debate. PURPOSE: To systematically evaluate the safety, fixation durability, and functional outcomes of cementless primary femoral stems in rTHA. METHODS: Following PRISMA guidelines (PROSPERO: CRD420251232433), we searched MEDLINE, Embase, Cochrane, and Web of Science through November 2025. Risk of bias was assessed using RoB-2 and ROBINS-I. Pooled event rates were calculated using a random-effects model. RESULTS: Twenty-one studies involving 2,109 rTHAs were analyzed over a mean follow-up of 97.6 months, primarily involving Paprosky type I and II defects. The pooled aseptic loosening rate was 2.96% (95% CI 2.28-3.73), while the overall complication rate was 14.34% (95% CI 12.87-15.86). Reoperations occurred in 9.65% of cases (95% CI 8.42-10.94), frequently due to aseptic loosening. Functional outcomes were favorable, evidenced by a mean Harris Hip Score of 81.03 at final follow-up. CONCLUSION: Cementless primary femoral stems are a reliable option for rTHA in patients with preserved metaphyseal bone, demonstrating low aseptic loosening rates and favorable functional outcomes at mid- to long-term follow-up. While these results support their use, further high-quality comparative research is necessary to define specific indications against revision-specific implants.