Abstract
BACKGROUND: Osteochondral allografting is an option for successful treatment of large articular cartilage defects. Use of osteochondral allografting is limited by graft availability, often because of loss of chondrocyte viability during storage. QUESTIONS/PURPOSES: The purpose of this study was to compare osteochondral allografts implanted in canine knees after 28 days or 60 days of storage for (1) initial (1 week) safety and feasibility; (2) integrity and positioning with time (12 weeks and 6 months); and (3) gross, cell viability, histologic, biochemical, and biomechanical characteristics at an endpoint of 6 months. METHODS: With Institutional Animal Care and Use Committee approval, adult dogs (n=16) were implanted with 8-mm cylindrical osteochondral allografts in the lateral and medial femoral condyles of one knee. Osteochondral allografts preserved for 28 or 60 days using either the current tissue bank standard-of-care (SOC) or a novel system (The Missouri Osteochondral Allograft Preservation System, or MOPS) were used, creating four treatment groups: SOC 28-day, MOPS 28-day, SOC 60-day, and MOPS 60-day. Bacteriologic analysis of tissue culture and media were performed. Dogs were assessed by radiographs and arthroscopy at interim times and by gross, cell viability, histology, biochemistry, and biomechanical testing at the 6-month endpoint. RESULTS: With the numbers available, there was no difference in infection frequency during storage (5% for SOC and 3% for MOPS; p=0.5). No infected graft was implanted and no infections occurred in vivo. MOPS grafts had greater chondrocyte viability at Day 60 (90% versus 53%; p=0.002). For 60-day storage, MOPS grafts were as good as or better than SOC grafts with respect to all outcome measures assessed 6 months after implantation. CONCLUSIONS: Donor chondrocyte viability is important for osteochondral allograft success. MOPS allows preservation of chondrocyte viability for up to 60 days at sufficient levels to result in successful outcomes in a canine model of large femoral condylar articular defects. CLINICAL RELEVANCE: These findings provide a promising development in osteochondral allograft technology that can benefit the quantity of grafts available for use and the quality of grafts being implanted.