Sex-Based Differences in Clinically Significant Outcome Achievement Following Primary Osteochondral Allograft Transplantation of the Knee at a Minimum 5-Year Follow-up

Background: Primary osteochondral allograft transplantation (OCA) of the knee has been shown to improve patient-reported outcome measure (PROM) scores at various follow-up time points. However, studies analyzing the effects of patient sex on primary OCA outcomes remain limited and show conflicting results. Purpose: To compare PROM scores and clinically significant outcome (CSO) achievement rates at a minimum 5-year follow-up between male and female patients who underwent primary OCA of the knee. Study Design: Cohort study; Level of evidence, 3. Methods: A prospectively collected database was queried for patients who underwent primary OCA, regardless of the presence of concomitant procedures, between January 2003 and January 2018. Inclusion criteria consisted of (1) primary OCA, (2) a minimum 5-year follow-up, and (3) age >18 years at the time of OCA. Patient characteristics, intraoperative variables, PROM scores, reoperations, and failures were compared. Rates of achieving the CSOs of the minimal clinically important difference (MCID), patient acceptable symptomatic state (PASS), and substantial clinical benefit (SCB) were compared at 5-year follow-up for the International Knee Documentation Committee (IKDC) score, Lysholm score, and Knee Injury and Osteoarthritis Outcome Score (KOOS). Regression analyses were performed to determine the factors associated with achieving the MCID, PASS, or SCB. Results: A total of 235 patients (119 female, 116 male) with a mean age of 31.0 ± 9.5 years, a mean follow-up of 6.5 years, and a mean body mass index of 26.7 ± 4.2 kg/m 2 were included in this study. Male patients had a higher body mass index (28.0 ± 4.3 vs 25.5 ± 3.8 kg/m 2 , respectively; P < .001), larger medial femoral condyle defects (20.2 ± 4.5 vs 17.7 ± 3.5 mm, respectively; P < .001), and larger lateral femoral condyle defects (20.3 ± 4.0 vs 18.1 ± 3.1 mm, respectively; P = .002) and were more likely to undergo concomitant osteotomy (24.1% vs 13.4%, respectively; P = .036), particularly concomitant high tibial osteotomy (14.7% vs 3.4%, respectively; P = .002), compared with female patients. At baseline, male patients had higher IKDC (41.8 ± 15.1 vs 33.3 ± 15.2, respectively; P = .003) and KOOS Sport (35.2 ± 24.1 vs 25.1 ± 22.0, respectively; P = .032) scores compared with female patients. At a minimum 5-year follow-up, female patients demonstrated higher Lysholm (79.6 ± 15.9 vs 73.8 ± 15.6, respectively; P = .026) and KOOS Pain (82.6 ± 16.9 vs 79.1 ± 13.7, respectively; P = .049) scores and achieved the MCID for the KOOS Sport (75.7% vs 46.7%, respectively; P = .015), the PASS for the KOOS Quality of Life (89.6% vs 67.3%, respectively; P = .003), and the SCB for the KOOS Sport (64.9% vs 23.3%, respectively; P < .001) at higher proportions than male patients. On multivariate regression analysis, male sex was associated with decreased odds of achieving the MCID (odds ratio, 0.234 [95% CI, 0.086-0.636]; P = .004) and SCB (odds ratio, 0.433 [95% CI, 0.205-0.917]; P = .028) for the IKDC score. Reoperations occurred in 37.9% of patients, and failure occurred in 26.8% of patients, with male and female patients demonstrating comparable rates for both. Conclusion: Despite male patients exhibiting higher preoperative scores for certain PROMs, female patients demonstrated higher or comparable postoperative PROM scores and CSO achievement rates after primary OCA of the knee at a minimum 5-year follow-up. Male sex was significantly associated with decreased odds of achieving the MCID and SCB for the IKDC score.