The power of tendon autograft in osteochondral defects: one step closer to hyaline cartilage.

OBJECTIVE: This study aimed to investigate the role of combined treatment of tendon autograft and microfracture technique in the formation of hyaline cartilage tissue, which has a very limited regeneration capacity, in an experimental osteochondral defect model created in the rabbit knee. METHOD AND MATERIALS: Forty-three New Zealand rabbit knee joints were used in the study. Rabbits were divided into five groups: Tendon autograft-microfracture, Tendon autograft, Microfracture, Empty defect (Sham) group, and Intact group. After creating a full-thickness cartilage defect in the right knee medial femoral condyle of the rabbits, the treatment methods belonging to the groups were applied. At the end of the six-week follow-up period, macroscopic and microscopic evaluations were made. Regenerative processes were evaluated by means of stereological, histopathological, immunohistochemical, and electron microscopic techniques on the sections obtained from paraffin and resin blocks. Newly formed cartilage and connective tissue volumes were analyzed with volume fraction. RESULTS: In rabbits that received a tendon autograft, a smooth surface and a cartilage surface compatible with the surrounding tissue were observed, while a fibrous and defective healing was observed in the microfracture group. In the empty defect (Sham) group, healing was minimal. In immunohistochemical analyses, higher cartilage matrix formation and type II collagen structure were detected in the tendon autograft groups. In scanning electron microscopic evaluation, healthy isogenous groups were observed in the group that received tendon autograft and microfracture treatment. CONCLUSION: The use of tendon autograft allows chondrocyte adhesion and proliferation as a cytoskeleton, providing a better regeneration more like healthy cartilage tissue.