Restoration of the enthesis of the rotator cuff

髋端是肌腱向骨传递力的重要部位，肌腱的胶原纤维通过纤维软骨进入骨。然而，很少有报道观察到损伤的髋端修复过程。从1997年开始，我们开始了对具有特殊解剖结构的髋端修复过程的基础研究。本研究结果表明，进入骨内的胶原纤维的修复过程随着肌腱重新附着的骨表面的不同而不同。在愈合期间，远端肌腱修复修复了四层终端，而对钙化纤维软骨层的肌腱修复则大大延迟了纤维向骨的发育。根据骨小梁的重塑，纤维与松质面形成连接。基于这些结果，在临床环境中，传统的将肩袖植入松质骨的手术方法被证明是合理的（J Shoulder肘关节外科，2001,in press）。此外，为了更清楚地了解胶原蛋白附着于松质骨的精细过程，我们引入了扫描电镜观察。因此，新形成的胶原纤维与松质骨的连接开始于术后两周形成新的胶原纤维和编织骨。术后4周，排列整齐的胶原纤维成束聚集并连接成编织骨。术后6周，胶原蛋白束变得致密且排列良好，形成与骨的安全连接。这是首次报道肌腱锚定进入松质骨的早期过程（J Orthop Res, 2001, in press）。根据这些研究，我们从组织学上观察了肌腱向松质骨的修复过程，认识到良好的血液供应和足够的张力诱导了肌腱向骨的愈合过程。在未来的研究中，我们应该考虑一种理想的方法来重建靠近骨的肌腱缺损。

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.