Restoration of the enthesis of the rotator cuff

点击翻译按钮获取中文摘要

Enthesis is an important site of force transmission through tendon to bone, and collagen fibers of tendons insert into bone via fibrocartilage. However, there were few reports in which repair process of injured enthesis was observed. From 1997, we instituted basic research for repair process of enthesis which has characteristic anatomical structure. As a result of this research, repair process of collagen fibers which enter into bone varies according to the surface of bone on which tendon is re-attached. Tendon repair to distal tendon ends restored the four-layered enthesis in the healing period, whereas tendon repair to the calcified fibrocartilage layer considerably delayed fiber development into bone. Fiber connection to cancellous surface developed according to the remodeling of trabecular bone. Based on these results, in clinical settings, the traditional surgical procedure of the rotator cuff into cancellous bone was proved to be reasonable (J Shoulder Elbow Surg, 2001, in press).Furthermore, to make clear the fine the process of collagen attachment into cancellous bone, we introduced scanning electron microscope observation. In consequence, connection of newly formed collagen fibers into cancellous bone initiated by forming both new collagen fibers and woven bone at two postoperative weeks. At four postoperative weeks, aligned collagen fibers gathered in bundle and connected into woven bone. At six postoperative weeks, collagen bundles became dense and well aligned forming secure connection to bone. This is the first report in which early process of tendon anchoring into cancellous bone was demonstrated (J Orthop Res, 2001, in press).According to these studies, we observed repair process of tendon into cancellous bone histologically, and realized that good blood supply and adequate tension induced healing process of tendon to bone. In future study, we should consider an ideal method to reconstruct defected tendon close to bone.