Middernacht Bart, De Roo Pieter-Jan, Van Maele Georges, De Wilde Lieven F
Department of Orthopaedic Surgery and Traumatology, Ghent University Hospital, De Pintelaan 185, B-9000, Ghent, Belgium.
Clin Orthop Relat Res. 2008 Jun;466(6):1410-8. doi: 10.1007/s11999-008-0187-6. Epub 2008 Mar 6.
The reverse total shoulder prosthesis provides successful functional outcome in many patients with rotator cuff tear arthropathy. However, scapular notching, a direct consequence of mechanical impingement between the humeral prosthesis and the glenoid, remains a major concern. We presumed a better knowledge of the anatomy of the scapula would enable design or placement modifications to minimize this phenomenon. After establishing a uniform spatial reference system using easy locatable surgical reference points and planes, we analyzed 200 dry bony scapulae and defined the glenoid and infraglenoid anatomy relative to the reference system. The bony rim of the two inferior quadrants of the glenoid forms a semicircle the center of which can be used perioperatively as an easy locatable bony reference point. The infraglenoid tubercle varies in width and length, and can interfere with the humeral part of the reverse prosthesis, creating scapular notching. To avoid notching, we suggest using a convex base plate with a smaller radius than currently used, placing it as low as possible with a 42-mm glenosphere eccentrically assembled to create a posterior offset. If prosthetic overhang cannot be obtained, we suggest removing part of the infraglenoid tubercle.
反式全肩关节置换假体在许多肩袖撕裂性关节病患者中取得了成功的功能效果。然而，肩胛切迹作为肱骨头假体与关节盂之间机械撞击的直接后果，仍然是一个主要问题。我们推测，更好地了解肩胛骨的解剖结构将有助于进行设计或放置调整，以尽量减少这种现象。在使用易于定位的手术参考点和平面建立统一的空间参考系统后，我们分析了200个干燥的肩胛骨，并相对于参考系统定义了关节盂和关节盂下的解剖结构。关节盂两个下象限的骨缘形成一个半圆，其中心可在手术中用作易于定位的骨参考点。关节盂下结节的宽度和长度各不相同，可能会干扰反式假体的肱骨头部分，从而导致肩胛切迹。为避免出现切迹，我们建议使用半径比目前使用的更小的凸形基板，尽可能将其放置得低一些，并偏心组装一个42毫米的关节盂球以形成后移。如果无法实现假体悬垂，我们建议切除部分关节盂下结节。
