Cryopreservation of osteo-chondral grafts in rabbits

To study the cryopreservation of osteoarticular allografts, a lateral femoral condyle of the rabbit was transplanted fresh, after uncontrolled freezing to -80 degrees C with 4 weeks preservation, and after freezing 1 degree C per min to -100 degrees C in 10 per cent dimethylsulphoxide medium with 4-week storage in liquid nitrogen. Autografts were used as controls. After 3 months, the incorporation of the grafted bone was good in all technically successful cases. The NADH2 diaphorase activity and 35S sulphate uptake indicated well-functioning chondrocytes in all autografts. In the allografts, areas lacking enzyme activity and lacking 35S uptake were observed in cartilages with otherwise normally functioning chondrocytes. No differences were found between the three allograft groups. We conclude that freezing permits reasonably good short-term bank preservation of cartilage. We found no difference between conventional freezing and controlled slow freezing with preservative.