Experimental Research Of Large Articular Cartilage Defect Repaired With Osteochondral Allografts By Cryopreservation

Objective To observe the effect of large articular cartilage defect repaired with osteochondral allografts by cryopreservation, and to provide experimental basis for clinical applications.Methods In this study, 36 male New Zealand White rabbits were randomly devided into 3 groups: donor group, experiment group, control group. Animals in donor group were sacrificed after osteochondral allografts had been prepared; In experiment group, the osteochondral allografts from animal tibia entocondyle by cryopreservation were transplanted; In control group, the osteochondral autografts were fixed in their own positions. Then, general observation, X-ray examination, histological test, Wakitani score and immunohistochemical examination were observed.Results①General observation of osteochondral grafts: Range of motion of all joints was normal. There was no intracapsule ashesion and effusion in each joint. Osteochondral autografts in experiment group had the similar height and color as the surrounding articular cartilage. Articular surface was even. Basilar part of the autografts had no obvious margin. Articular cartilage in control group was smoothly and had the same height as the surrounding host cartilage.②X-ray examination: Fracture lines of all joints were blurry, and the positions of all osteochondral grafts were all right.③Histological test: All the defect were covered by hyaline cartilage. Chondrocytes were arrayed orderly with a plenty of secreted cartilage maxtrix. No lymphocytes and plasmacytes were infiltrative peripherally.④There was no significant difference of Wakitani score between experiment group and control group(4.7,4.3,P>0.05).⑤T ypeⅡcollagen immunohistology staining of repairing cartilage was positive both in experiment group and in control group.Conclusion The osteochondral allografts by cryopreservation can repair the large defect of articular cartilage effectively, and have the similar histological characteristics as the osteochondral autografts. No immunological rejecion is found.