Return to Sport and Sports-Specific Outcomes After Osteochondral Allograft Transplantation in the Knee: A Systematic Review of Studies With at Least 2 Years' Mean Follow-Up

Purpose: To report current data on return-to-sport rates and sports-specific patient-reported outcomes after osteochondral allograft (OCA) transplantation for cartilage defects of the knee. Methods: We performed a systematic review according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines that included studies from 1975 to 2018 with a minimum 2-year mean follow-up that reported return-to-sport rates or sports-specific patient-reported outcomes. Outcomes, reoperations, and complications were provided in table format, and a subjective analysis was performed. Results: This review included 13 studies with 772 patients who underwent OCA transplantation at a mean of 24 to 91 months' follow-up. The return-to-sport rate ranged from 75% to 82%. For patient-reported outcomes, the Knee Injury and Osteoarthritis Score Sport increased in 4 studies, the Tegner activity scale score increased in 3 studies but decreased in 1, and the Marx activity scale score increased in 1 study but decreased in 2. Studies reporting improvements in the Cincinnati Knee Score and Knee Injury and Osteoarthritis Score Sport reached the minimal clinically important difference. The reoperation rate was high (ranging from 34% to 53% in more than half of studies), with reoperations primarily performed for loose body removal or debridement. Conclusions: This systematic review of 13 studies suggests that OCA transplantation for cartilage defects allows most athletes to return to sport (range, 75%-82%). Most studies reported improvements in sports-specific patient-reported outcomes at follow-up and reached the minimal clinically important difference. However, the reoperation rate was high in several studies, with a large percentage of patients requiring loose body removal or debridement. The long-term survival of the allografts is largely unknown, but this study suggests OCA transplantation consistently improves function in athletes with chondral injuries.