Abstract:

BACKGROUND: Rotator cuff injuries can be treated by many methods, but their mechanisms of repairing are still unclear, especially for tendon-bone injury.
OBJECTIVE: To establish continuous passive motion (CPM) models following repairing acute rupture of supraspinatus tendon, to observe the effect of CPM on histological changes of tendon-bone, and to explore the role of CPM in the postoperative rehabilitation following acute rotator cuff injury .
METHODS: Twenty adult male New Zealand white rabbits were selected, 2 of them were randomly sacrificed as controls, and the remained animals were established rabbit rotator cuff injury prosthetic experimental models. Two rabbits were sacrificed as model controls, and others were divided into the CPM (n=8) and non-CPM (n=8) groups. CPM was performed on rabbits in the CPM group at 2 weeks after model preparation. Rabbits in the non-CPM were housed regularly. Two rabbits were sacrificed at weeks 2, 4, 6 and 8 after training, and the gross and histological observation of tendon-bone interface was performed. 
RESULTS AND CONCLUSION: Compared with the non-CPM group, the CPM group presented serious inflammatory response at 2 weeks, which was obviously decreased at 4 weeks. After 6 weeks, the number of fibroblasts of the CPM group was increased compared with the non-CPM group. After 8 weeks, the organizational structure study showed that fibroblasts in the CPM were greater than that of the non-CPM group, with orderly shape and arrangements. The results demonstrated that CPM can contribute to rabbit supraspinatus tendon-bone repair, so as to promote functional recovery.