Outcomes of Osteochondral Allograft Transplantation: A Comparative Study of BioUni and Snowman Techniques for Ovoid Lesions

Background: Treatment of large articular cartilage lesions of the knee includes surgical options one of which includes cartilage replacement therapies. Among these therapies include osteochondral allograft (OCA) transplantation, which can be performed utilizing a BioUni® (Arthrex BioUni® Instrumentation System; Arthrex, Naples, FL) replacement and a ‘snowman’ technique of repair. Hypothesis/purpose: To compare clinical and radiographic outcomes in patients who have undergone multiplug OCA transplantations utilizing a BioUni® replacement and a ‘snowman’ technique of repair. Methods: Patients who underwent OCA transplantation utilizing a snowman technique or BioUni® replacement between January 1(st), 2012 and December 31(st), 2018, and who had a minimum 1-year follow-up at the same institution were identified for inclusion in this study via current procedural terminology (CPT) codes. Charts of included patients were reviewed for injury and treatment details as well as demographic information. Imaging studies and operative reports were reviewed and pre and postoperative subjective and objective outcome measures were recorded. Results: Twenty-eight patients underwent OCA transplantation with either BioUni® replacement (n=5) or with snowman technique repair (n=23). Defects in both groups had similar characteristics including size, area, location, and classifications. Patient-reported outcomes using the Knee Injury and Osteoarthritis Outcome Score-Joint Replacement (KOOS-JR), International Knee Documentation Committee (IKDC), and Physical Health Composite Score (PCS-12) were similar at baseline and increased post-operatively for both groups with no significant differences between techniques after a mean follow-up of 2.77 ± 0.83. Although it did not reach significance, the snowman group had higher rates of knee-related complications (13%) and need for revision surgery (22%) when compared to BioUni® (0% and 0%, respectively). Conclusion: The use of both BioUni® and snowman techniques for large, unicondylar articular cartilage lesions of the femoral condyle demonstrate improved patient-reported outcomes at short-term follow-up. The use of the snowman technique presents relatively higher rates of revision similar to previous studies with no statistical difference in patient-reported outcomes when compared to those of a single plug OCA using a BioUni® system.