 Osteocondrol allograft transplantation offers favorable short-to-midterm outcomes for patients with cartilage defects in the knee. But the rate of re-operation is reportedly high, and few studies have explored the mid-to-long-term outcomes of transplantation. To address this gap, researchers analyzed significant outcomes, failures, and graft survival rates over a minimum of five years in patients undergoing OCA transplantation of the femoral condyles. Despite a high re-operation rate, findings suggest that OCA transplantation is associated with significant clinical improvement at mid-to-long-term follow-up. The researchers followed up with 160 patients for an average of 7.7 years after OCA transplantation. All patient-reported outcomes related to joint and physical health improved significantly between baseline and final follow-up. These included international knee documentation committee scores, LISOM scores, short-form 12 scores for physical health, and knee injury and osteoarthritis outcome scores for symptoms, pain, activities of daily living, sports performance, and quality of life. Short-form 12 scores for mental health were the only patient-reported outcome that did not improve significantly over the follow-up period. 56 patients who had pre- and post-operative IKDC scores and had not failed treatment were available for assessment of minimal clinically important difference and significant clinical benefit. At final follow-up, 42 of these patients achieved MCID and 33 achieved SCB. Failure to meet these benchmarks was associated with pre-operative knee effusion, number of re-operations, and previous meniscal procedures. While nearly 40% of patients required re-operation, 5 and 10-year graft survival rates exceeded 80%, with only 34 graft failures recorded. Failure was independently associated with greater BMI, longer symptom duration, number of previous procedures, and previous failed cartilage debridement. Overall the findings indicate that OCA transplantation is associated with significant clinical improvement and durability at mid- to long-term follow-up. In fact, maintenance of clinically significant outcomes can be expected in most patients at a mean of 7.7 years after OCA transplantation, despite a high re-operation rate that could interfere with maintaining favorable outcomes. Most patients can be expected to avoid long-term graft failure.