Clinical Factors Affecting Outcomes of Osteochondral Allograft Transplantation: A Multivariable Analysis of 560 Knees

Background: Osteochondral allograft (OCA) transplantation is a successful treatment option for focal chondral and osteochondral lesions; however, outcomes vary by patient and intraoperative variables. Previous studies have compared outcomes of OCA transplantation using basic descriptive and surgical data; nonetheless, they do not account for possible confounding variables. Hypothesis/Purpose: The purpose of this study was to report overall survivorship of OCA transplantation using a large, long-term registry from a specialty cartilage practice and utilize a multivariable model to identify factors that best predict treatment failure. The use of a multivariable analysis allows for the simultaneous assessment of multiple risk factors while controlling for the influence of confounding factors. Study Design: Case series; Level of evidence, 4. Methods: We identified 527 patients (560 knees) who underwent OCA transplantation between 1997 and 2021 for focal chondral lesions by a single surgeon and had a minimum follow-up of 2 years. Treatment failure was defined as any surgery involving the removal of the allograft or conversion to arthroplasty. Variables associated with treatment failure in univariate analyses were included in a multivariable logistic regression model to identify those with the greatest effect. Results: The mean age of the participants was 32.6 years, the mean follow-up was 8.2 years, and 62% were men. Treatment failure occurred in 89 knees (15.9%) at a median of 3.9 years postoperatively. Graft survivorship was 89% at 5 years, 83% at 10 years, and 75% at 15 years. Univariate analysis identified patient age, body mass index (BMI), diagnosis type, anatomic location, number of grafts, total graft size, and number of previous surgeries to be associated with treatment failure. However, in the multivariate analysis, only patient age, BMI, diagnosis, and graft size independently predicted a higher risk of treatment failure after controlling for other variables. Specifically, patients who were aged ≥30 years were 2.13 times more likely than younger patients to experience a treatment failure. Patients with a BMI of ≥30 kg/m 2 were 2.24 times more likely to experience treatment failure compared with patients with a BMI of <30 kg/m 2 . Patients with degenerative chondral lesions, avascular necrosis, or osteoarthritis were more likely to experience treatment failure compared with patients with osteochondritis dissecans. Grafts with a total surface area of >8 cm 2 were 2.12 times more likely to fail than those ≤8 cm 2 . Conclusion: OCA transplantation performed in all settings yielded effective long-term results, with graft survivorship of 83% at 10 years postoperatively. Patient age ≥30 years, BMI of ≥30 kg/m 2 , diagnosis, and graft size >8 cm 2 were independently associated with a higher risk of treatment failure when controlling for other variables. Understanding the effect of clinical variables in a multivariable model is useful for counseling patients on the odds of treatment failure.