A two-degree-of-freedom hip exoskeleton device for an immature animal model of exercise-induced Legg-Calvé-Perthes disease.

Legg-Calvé-Perthes disease (LCPD) is a significant problem in healthcare because it so commonly affects young adults and immature athletes, primarily gymnasts. In this paper, a two-degree-of-freedom (2-DOF) hip exoskeleton device was developed for study on an immature animal model of exercise-induced LCPD. The exoskeleton device can reproduce the repetitive actions and forceful centrality impingements on the coxafemoral head that occur in sports such as gymnastics and acrobatics. It initiated a new method rather than the traditional medical or physiological operation method to establish an animal model of LCPD and allowed for the development and testing of new treatments. Ten immature New Zealand white rabbits were selected for the experiment. Their right legs were driven to achieve repetitive extension/ flexion and abduction/adduction beyond the normal range of motion, with centrality impingements at the maximum flexion position, while their left legs were kept in the initial healthy status and acted as the comparing reference. Four weeks later, the basic symptoms of early LCPD of the femoral head appeared. The results of X-ray, magnetic resonance imaging (MRI), gross anatomy observation, and H-E section also revealed it.