Outcomes of Osteochondral Allograft Transplantation in the Knee

PURPOSE: The objectives of this study were (1) to conduct a systematic review of clinical outcomes after osteochondral allograft transplantation in the knee and (2) to identify patient-, defect-, and graft-specific prognostic factors. METHODS: We searched PubMed, Medline, EMBASE, and the Cochrane Central Register of Controlled Trials. Studies that evaluated clinical outcomes in adult patients after osteochondral allograft transplantation for chondral defects in the knee were included. Pooled analyses for pertinent continuous and dichotomous variables were performed where appropriate. RESULTS: There were 19 eligible studies resulting in a total of 644 knees with a mean follow-up of 58 months (range, 19 to 120 months). The overall follow-up rate was 93% (595 of 644). The mean age was 37 years (range, 20 to 62 years), and 303 patients (63%) were men. The methods of procurement and storage time included fresh (61%), prolonged fresh (24%), and fresh frozen (15%). With regard to etiology, the most common indications for transplantation included post-traumatic (38%), osteochondritis dissecans (30%), osteonecrosis from all causes (12%), and idiopathic (11%). Forty-six percent of patients had concomitant procedures, and the mean defect size across studies was 6.3 cm(2). The overall satisfaction rate was 86%. Sixty-five percent of patients (72 of 110) showed little to no arthritis at final follow-up. The reported short-term complication rate was 2.4%, and the overall failure rate was 18%. Heterogeneity in functional outcome measures precluded a meta-analysis; a qualitative synthesis allowed for the identification of several positive and negative prognostic factors. CONCLUSIONS: Osteochondral allograft transplantation for focal and diffuse (single-compartment) chondral defects results in predictably favorable outcomes and high satisfaction rates at intermediate follow-up. Patients with osteochondritis dissecans and traumatic and idiopathic etiologies have more favorable outcomes, as do younger patients with unipolar lesions and short symptom duration. Future studies should include comparative control groups and use established outcome instruments that will allow for pooling of data across studies. LEVEL OF EVIDENCE: Level IV, systematic review of Level IV studies.