Cartilage repair by free periosteal grafts in the knees of pigs: A histologic study

Background and purpose: Periosteal grafts may result in cartilage formation and, therefore, have the potential to repair cartilage defects. We evaluated the histologic results of free periosteal grafts for the repair of full-thickness cartilage defects in pigs. Methods: A free autogenous periosteal flap from the proximal tibia was grafted to a size-matched, full-thickness articular defect on the lateral femoral condyle of the knees of 12 pigs. The same defect on the medial femoral condyle was used as a control lesion. Biopsies were performed at 4, 8, and 12 weeks after grafting. Results: The control lesions showed dense fibrous tissue with no evidence of cartilage-like tissues. The predominant tissues after grafting were mixtures of fibrous tissue, fibrocartilage, mesenchyme tissue, and occasional bone islands, but no cartilage tissue was identified. The tissue distribution did not change in the same knee from the week 4 to the week 8 biopsy; nonetheless, there were interindividual variations in tissue distribution. Conclusions: The results of this study do not support the use of free periosteal transplantation for full-thickness cartilage defects of the knee.