Sex Mismatch Does Not Affect Outcomes or Graft Survival After Osteochondral Allograft Transplantation of the Knee: A Systematic Review

To investigate the effect of donor-recipient sex mismatch on outcomes following osteochondral allograft transplantation (OCAT) of the knee, with a focus on graft survivorship, complications, and patient-reported outcome measures. A systematic review was performed according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses 2020 guidelines. PubMed, Embase, and Scopus were searched through March 2025 for Level I-IV studies comparing sex-matched versus sex-mismatched OCAT for knee cartilage defects with a minimum follow-up of 2 years. Cadaveric, in vitro, and revision studies were excluded. Data extracted included patient demographics, lesion characteristics, graft type, surgical technique, patient-reported outcome measures, and postoperative complications. Risk of bias was assessed using the Methodological Index for Non-Randomized Studies. A total of 973 patients were included across 4 Level III or IV studies, with 613 receiving sex-matched and 360 receiving sex-mismatched grafts. Follow-up ranged from 3.3 to 5.4 years, with consistent use of fresh, press-fit osteochondral allografts across studies. Three studies found no significant differences in failure, reoperation, or patient-reported outcomes between matched and mismatched cohorts. One study reported a higher failure rate in the sex-mismatched group (21.2% vs. 6.9%, P = .02), particularly in male-donor-to-female-recipient cases. However, sex mismatch was not a consistent predictor of failure across studies. Donor-recipient sex mismatch in patients undergoing OCAT of the knee does not consistently affect graft survival or functional outcomes. Reported failure rates ranged from 5.2% to 21.2% across studies, with bipolar grafts being the most reliable predictor of failure. Given the absence of consistent differences in outcomes, routine sex matching does not appear necessary. Level IV, systematic review of Level III and IV studies.