Heterotopic transfer of fresh and cryopreserved autogenous articular cartilage in the horse.

Two 10 mm thick osteochondral grafts were harvested from the lateral aspect of the lateral trochlear ridge of the left talus in each of 10 anesthetized horses. The grafts were frozen in a 7.5% DMSO solution and stored in liquid nitrogen. The horses were anesthetized again on day 14 and the thawed grafts were press-fitted into drill holes in the trochlear ridges of the right stifle. A fresh graft was transferred from the right hock to the left stifle. To control for the effects of surgery, another fresh graft was transferred from the right stifle to the left stifle. The result was two grafts in each femoropatellar joint. Fresh and frozen osteoarticular autografts appeared to maintain a durable weight-bearing surface for 3 months; however, the fresh grafts were clearly superior. Frozen grafts had fewer living chondrocytes, decreased safranin-O staining, and decreased SO435 uptake. Graft stability and articular surface congruency were determining factors in the outcome of all grafts. Since the availability of osteochondral autografts is limited, further work on the use of preserved allogeneic osteochondral tissue is warranted.