Long term observations on the articular cartilage and autologous costal cartilage transplanted to osteochondral defects on the femoral head. A histological, autoradiographic (35S-sulphate) and microchemical (glycosaminoglycan) study in adult rabbits.

Abstract

In 20 adult rabbits autologous costal cartilage was transplanted to an osteochondral defect on the femoral head. After 1, and 11/2 years the tissue of the transplant area and the articular cartilage from the operated and non-operated joints were studied. The histological and autoradiographic (35S-sulphate) study showed that the articular surface and the bulk of the transplant area consisted mainly of viable cartilaginous tissue showing signs of degeneration to varying degree. Also, fibrous tissue was found on the articular surface of the transplant area. The quantitative microchemical study of glycosaminoglycans, hydroxyproline and calcium was made on microdissected freeze-dried material. The total hexosamines and the keratan-sulphate and/or glycoprotein fraction were lower in the transplant than in the articular cartilage from the operated joints while the contrary was true for chondroitin sulphate. The articular cartilage from the operated joints showed a reduction of total hexosamines and of all glycosaminoglycan fractions compared to the non-operated joints. These changes were especially pronounced in samples showing signs of degeneration in Azur-Astained, freeze-dried sections. It is suggested that in early and slight superficial articular cartilage degeneration the glycoprotein and/or keratan-sulphate fraction is reduced while chondroitin-sulphate remains relatively unaltered.