Repair of osteochondral defects with allogeneic tissue engineered cartilage implants

The objective of this study was to evaluate the effect of allogeneic tissue engineered cartilage implants on healing of osteochondral defects. Rabbit chondrocytes were cultured in monolayer, then seeded onto biodegradable, th ree-dimensional polyglycolic acid meshes. Cartilage constructs were culture d hydrodynamically to yield tissue with relatively more (mature) or less (i mmature) hyalinelike cartilage, as compared with adult rabbit articular car tilage. Osteochondral defects in the patellar grooves of both stifle joints either were left untreated or implanted with allogeneic tissue engineered cartilage. Histologic samples from in and around the defect sites were exam ined 3, 6, 9, and 12, and 24 months after surgery. By 9 months after surger y, defect sites treated with cartilage implants contained significantly gre ater amounts of hyalinelike cartilage with high levels of proteoglycan, and had a smooth, nonfibrillated articular surface as compared to untreated de fects. In contrast, the repair tissue formed in untreated defects had fibri llated articular surfaces, significant amounts of fibrocartilage, and negli gible proteoglycan, These differences between treated and untreated defects persisted through 24 months after surgery. The results of this study sugge st that the treatment of osteochondral lesions with allogeneic tissue engin eered cartilage implants may lead to superior repair tissue than that found in untreated osteochondral lesions.