The effect of leg lenghening on the articular cartilage of the rabbit tibia

Lee, Duk Yong,; Choi, In Ho; Chung, Chin Youb; Tae, Suk Kee; Park, Yong Jun

Abstract

The purpose of this study is to investigate the effect of lengthening in long bones on the articular carilage by observing the changes in articular cartilage, Fifty-seven rabbits of growing period were divided into four lengthening groups; 5%, 10%, 20%, and 30%. Lengthening by callotasis that was done on the left tibiae and right tibiae were used as control. After lengthening histopathological, histochemical and autoradiographic studies were done on the proximal and distal tibial articular cartilages. That following observations were made. 1. As compared with controls, statistically significant degenerative changes were noted in proximal and distal articular cartilages when the tibiae were lengthened 10% or more. 2. In the proximal joints, the changes were significant between 10% and 20% lenghtening groups, but not between the 20% and 30% lengthening groups. 3. In the distal joints, the changes were significant. Not only were there between 10% and 20% lengtening groups but also there were between 20% and 30% lengtening groups. 4.Degenerative changes were frequently found in the intermediate zone between the periphery and the center, where most of the weight is borne.5. Decrease in matrix content of degenerated articular cartilage was noted by histochemical studies using safranin-0 and Alcian-blue.6. Autoradiography with S04 was done to quantitate matrix content of articular cartilage, and the mean uptake ratio of the articular cartilage was slightly higher than others in the 30% lengthening group. This esuggest decreased matrix synthesis, but no statistical significance was found. Following conclusion were drawn from above observations. 1. In rabbits, tibial lengthening tended to cause microscopic degenerative changes, and the changes begun to appear when the tibiae were lengthened 10% or more. 2. When lengthened over 20%, the changes became more pronounced in the distal joint than in the proximal joint.