Prospective Assessment of Outcomes After Primary Unipolar, Multisurface, and Bipolar Osteochondral Allograft Transplantations in the Knee: A Comparison of 2 Preservation Methods

Abstract

Background: Articular cartilage lesions in the knee remain a challenging clinical problem. Hypothesis: A novel graft preservation method combined with surgical technique and patient management improvements would lead to consistently successful outcomes after osteochondral allograft (OCA) transplantation. Study Design: Cohort study; Level of evidence, 3. Methods: With institutional review board approval and informed consent, patients were prospectively enrolled into a registry to follow outcomes after OCA transplantation. Patients were included when ≥1-year follow-up data were available, including complications and reoperations, patient-reported outcome measures (PROMs), compliance with rehabilitation, revisions, and failures. Results: For patients meeting inclusion criteria (N = 194), mean ± SD age was 37.9 ± 12.2 years and mean BMI was 28.9 ± 5; 38% received unipolar transplants (44% multisurface) and 62% received bipolar transplants. OCAs were preserved by standard tissue bank methods (standard preservation [SP]; 29%) or the novel method (Missouri Osteochondral Preservation System [MOPS]; 71%). Initial success rates were 79% for all cases combined, 60% for SP, and 84% for MOPS. MOPS cases were significantly ( P = .028) more likely to be associated with successful outcomes when compared with SP cases. PROMs improved significantly ( P < .05) for all cohorts through 3 to 4 years of follow-up. Revisions were performed in 19 cases (10%). MOPS grafts were associated with a significantly ( P = .0014) lower revision rate (5%) than SP grafts (21%). Failures occurred in 26 patients (13%), with all undergoing total knee arthroplasty. Bipolar cases were significantly ( P = .008) more likely to be associated with failure. MOPS grafts were associated with a significantly ( P = .048) lower failure rate (11%) than were SP grafts (19%). Noncompliance with the prescribed rehabilitation protocol was significantly ( P = .00008) more likely to be associated with failure. Conclusion: Prospective data for 194 cases revealed that OCA transplantation for unipolar, multisurface, and bipolar cartilage restoration can be associated with consistently successful outcomes. The 5% revision rate, 11% failure rate, 82%-94% survival probability estimates, and continually improving PROMs through postoperative 3 to 4 years underscore major advances in outcomes as compared with previous reports. These encouraging results were realized with the use of a novel graft preservation method; autogenous bone marrow concentrate pretreatment of donor bone; advancements in graft cutting, implantation, and stabilization techniques; and procedure-specific rehabilitation protocols.