Evaluating Donor-Recipient Sex Mismatch in Anterior Cruciate Ligament Reconstruction With Allograft: Outcomes at 2 Years Postoperatively.

Abstract

Background: Female patients tend to suffer a greater risk of reinjury and worse patient-reported outcome measures (PROMs) after anterior cruciate ligament reconstruction (ACLR) than male patients, regardless of the graft type used.

Purpose/hypothesis: This study explored the role of donor-recipient sex mismatching to help explain these sex-based disparities in outcomes after ACLR with an allograft. The hypothesis was that allograft donor-recipient sex mismatch would adversely affect surgical outcomes at a 2-year follow-up, with male-to-female graft donations yielding the lowest rates of success.

Study design: Cohort study; Level of evidence, 3.

Methods: Patients who underwent primary ACLR with an allograft between 2012 and 2022 were eligible for recruitment. The following PROMs were collected from baseline through a 2-year follow-up: Knee injury and Osteoarthritis Outcome Score subscales, Marx activity rating scale, visual analog scale for pain, and Veterans RAND 12-Item Health Survey. Demographic and graft-specific variables were also collected. Sex-matched cases were compared with sex-mismatched cases and an identical subgroup analysis was performed for female patients only.

Results: Of the 112 included patients (N = 70 women), 59 (52.7%) were sex mismatched. The mean patient age was 40.7 ± 10.9 years, and the mean body mass index was 26.8 ± 4.7 kg/m². Most reconstructions (89.3%) used a semitendinosus tendon graft, with a mean implanted graft diameter of 9.7 ± 0.5 mm (quadrupled). Of the mismatched cases, 96.6% involved a male allograft donated to female recipients. Overall, the matched group demonstrated higher PROM scores across all time points compared with the mismatched group, although statistical significance was only reached for the Marx score at baseline (P = .012) and 1 year postoperatively (P = .022). In the female-only subgroup analysis, a larger graft diameter was measured in the mismatched cases (receiving male allografts) compared with the matched female cases (9.7 ± 0.6 vs 9.2 ± 0.4 mm, respectively; P = .002). Moreover, the mismatched cases tended to report better postoperative PROM scores, although this trend was not statistically significant.

Conclusion: The study findings indicated that male donors provided larger allografts than female donors, and that donor-recipient allograft sex matching did not contribute significantly to ACLR outcomes. Other factors may be more important to outcomes in female patients.