SummaryArticular cartilage repair is still a challenge in orthopaedic surgery. Although many treatment options have been developed in the last decade, true regeneration of hyaline articular cartilage is yet to be accomplished. In vitro experiments are useful for evaluating cell -matrix interactions under controlled parameters. When introducing new treatment options into clinical routine, adequate animal models are capable of closing the gap between in vitro experiments and the clinical use in human beings. We developed an animal model in the Gö ttingen minipig (GMP) to evaluate the healing of osteochondral or full-thickness cartilage defects. The defects were located in the middle third of the medial portion of the patellofemoral joint at both distal femurs. Chondral defects were 6.3 mm, osteochondral defects either 5.4 or 6.3 mm in diameter and 8 or 10 mm deep. In both defects the endogenous repair response showed incomplete repair tissue formation up to 12 months postoperatively. Based on its limited capability for endogenous repair of chondral and osteochondral defects, the GMP is a useful model for critical assessment of new treatment strategies in articular cartilage tissue engineering.

Generally, implants give rise to toxic reactions and favour the formation and propagation of local infections. Adherance of the soft tissue to the implant prevents the development of fluid filled cavities, thus being of particular interest as a prophylactic measure in arresting spread of infections. Teflon cylinders with an etched surface have been investigated by optical and electron microskopic means following subcutane implantation in mice. We were able to demonstrate closed tissue contact. Signs of toxic tissue reactions were completely absent.