Scanty integration of osteochondral allografts cryopreserved at low temperatures with dimethyl sulfoxide.

Purpose: To compare the integration of osteochondral allografts cryopreserved at different temperatures and different concentrations of dimethyl sulfoxide in an in vivo sheep animal model.

Methods: Thirty-six adult sheep were randomly allocated to 6 groups of allograft osteochondral transplantation. Six osteochondral cylinders were stored for 6 weeks at -80°C; 6 at -80°C with 10% dimethyl sulfoxide (DMSO); 6 at -80°C with 10% DMSO for 90 min; 6 at -186°C; 6 at -186°C with 10% DMSO; 6 at -186°C for 90 min. After transplantation, all animals were euthanized at 6 months. Harvested specimens underwent gross morphologic and histologic evaluation.

Results: We found no statistically significant differences when comparing the gross cartilage morphology and histopathologic scores of each group. The Mankin and OARSI scores and the modified Wakitani and OARSI scores showed a good correlation grade. The Mankin and modified Wakitani scores showed a fair correlation grade.

Conclusion: The cryopreservation protocols adopted in the present study provided scanty integration in an in vivo sheep model of osteochondral allograft transplantation. Therefore, their use in the clinical practice is discouraged.