Chondrocyte viability in refrigerated osteochondral allografts used for transplantation within the knee

Purpose: To evaluate cell viability and matrix characteristics of refrigerated osteochondral allografts implanted up to 44 days after harvest. Methods: Sixteen refrigerated allografts underwent histologic and ultrastructural examination and fluorescence excitation analysis prior to implantation. The average size of the graft implanted was 6.2 cm(2) ( 3.4 cm(2)). Refrigerated allografts averaged 30 days (range, 17 to 44 days) from donor expiration to implantation. Nine specimens underwent cell viability testing. The percent viability of refrigerated allografts prior to implantation averaged 67%. Results: No significant correlations were noted between histologic score, electron microscopy score, matrix staining percent (MSP) score, and viability. When time to implantation was assessed, an inverse correlation was noted with MSP score (r = .539) (P < 0.05), indicating less matrix staining in grafts refrigerated longer after harvest. Conclusion: The current data indicate that refrigerated osteochondral allografts can be maintained for up to 44 days with average chondrocyte viability of 67%.