Association of Sex Mismatch Between Allograft Donor and Recipient With 2-Year Surgical Outcomes After Anterior Cruciate Ligament Reconstruction

Introduction: It is well-known that the risk of ACL injury is higher in females. Female patients also tend to suffer greater risk of re-injury and worse patient-reported outcome measures (PROMs) after ACL reconstruction (ACLR), regardless of the graft type used. The causative elements of these disparities, however, have not been elucidated.

Purpose: To explore the potential role of donor-recipient sex mismatching in postoperative outcomes following ACLR with allograft.

Methods: Patients who underwent primary ACLR with an allograft between 2012-2022 were eligible for recruitment. Graft-specific variables and the following PROMs were collected at baseline with 2-year follow-up: the Knee Injury and Osteoarthritis Outcome Score pain and function subscales, Marx Activity Scale, Visual Analogue Scale, and Veteran’s Rand-12. Sex “matched” cases were compared to “mismatched” cases and an identical sub-analysis was performed for female patients only.

Results: Of the 113 patients analyzed, 60 were sex-mismatched. The average age of patients was 39.6±11.5 years. The majority of cases (89.4%) used a semitendinosus graft and the mean implanted graft diameter was 9.6±0.6mm (quadrupled). Of the mismatched cases, 96.7% involved a male-to-female allograft donation. The Marx Activity score was greater at baseline and at 1 year in the sex-matched group (P<0.05 for both), PROMs also tended to be better at all time points in the matched group. In the female-only sub-analysis, mismatched cases tended to have better PROMs postoperatively. Interestingly, the quadrupled male allografts implanted in these patients were also larger on average (9.3±0.4mm vs. 9.7±0.6mm, P=0.002).

Conclusion: These findings suggest donor-recipient sex matching does not contribute significantly to the outcomes of ACLR with allograft.”