Which Variables Predict Osteochondral Allograft Failure?

OBJECTIVES: Osteochondral allograft (OCA) transplantation is a valuable treatment option for chondral and osteochondral lesions of the knee. Understanding the impact of clinical variables on the outcome of OCA transplantation would be useful for counseling patients on the relative risk of the procedure. The purpose of this study was to determine which variables predicted treatment failure in a large cohort of patients undergoing OCA transplantation of the knee. METHODS: OCA transplantation was performed in 673 knees from 1997 to 2016; 489 had a minimum follow-up of two years. Average age was 32 years and 63% were male. Mean graft size was 8.9 cm2. Reoperations following the OCA transplantations were assessed, and treatment failure was defined as any procedure that involved removal of the allograft. Variables associated with treatment failure in univariate analyses (age, diagnosis, anatomic location, and graft size) were included in a logistic regression model. RESULTS: Treatment failure occurred in 78 knees (16%); 58 conversions to arthroplasty, 19 revision allografting, and 1 patellectomy. Age, diagnosis, and graft size independently predicted a higher risk of failure (Table 1). Patients who were ≥30 years old were 2.4 times more likely than younger patients to experience a treatment failure. Compared to patients with osteochondritis dissecans or traumatic chondral injury, patients with degenerative chondral lesions, avascular necrosis, or osteoarthritis were more likely to have allograft failure. Grafts >8 cm2 were 2.1 times more likely to fail than grafts ≤8 cm2. Anatomic location and number of grafts were associated with failure in univariate analyses, but not after controlling for other variables in the multivariate analysis. CONCLUSION: Older age, diagnosis of avascular necrosis or degenerative joint disease, and larger graft size were associated with higher risk of treatment failure. This data is useful in counseling individual patients on the risk of osteochondral allograft surgery.