Department of Orthopaedic Surgery & Sports Traumatology, Hôpital de L'Archet-University of Nice-Sophia-Antipolis, 151 Route de St Antoine de Ginestière, 06202 Nice, France.
Clin Orthop Relat Res. 2011 Sep;469(9):2558-67. doi: 10.1007/s11999-011-1775-4.
Scapular notching, prosthetic instability, limited shoulder rotation and loss of shoulder contour are associated with conventional medialized design reverse shoulder arthroplasty. Prosthetic (ie, metallic) lateralization increases torque at the baseplate-glenoid interface potentially leading to failure.
QUESTIONS/PURPOSES: We asked whether bony lateralization of reverse shoulder arthroplasty would avoid the problems caused by humeral medialization without increasing torque or shear force applied to the glenoid component.
We prospectively followed 42 patients with rotator cuff deficiency treated with bony increased-offset reverse shoulder arthroplasty. A cylinder of autologous cancellous bone graft, harvested from the humeral head, was placed between the reamed glenoid surface and baseplate. Graft and baseplate fixation was achieved using a lengthened central peg (25 mm) and four screws. Patients underwent clinical, radiographic, and CT assessment at a minimum of 2 years after surgery.
The humeral graft incorporated completely in 98% of cases (41 of 42) and partially in one. At a mean of 28 months postoperatively, no graft resorption, glenoid loosening, or postoperative instability was observed. Inferior scapular notching occurred in 19% (eight of 42). The absolute Constant-Murley score improved from 31 to 67. Thirty-six patients (86%) were able to internally rotate sufficiently to reach their back over the sacrum.
Grafting of the glenoid surface during reverse shoulder arthroplasty effectively creates a long-necked scapula, providing the benefits of lateralization. Bony increased-offset reverse shoulder arthroplasty is associated with low rates of inferior scapular notching, improved shoulder rotation, no prosthetic instability and improved shoulder contour. In contrast to metallic lateralization, bony lateralization has the advantage of maintaining the prosthetic center of rotation at the prosthesis-bone interface, thus minimizing torque on the glenoid component.
Level IV, therapeutic study. See Guidelines for Authors for a complete description of levels of evidence.
肩胛骨切迹、假体不稳定、肩关节旋转受限和肩部轮廓丧失与传统的内侧化设计反肩关节置换有关。假体（即金属）外侧化会增加基板-肩胛盂界面的扭矩，从而导致假体失败。
问题/目的：我们想知道反肩关节置换的骨性外侧化是否可以避免因肱骨内侧化而导致的问题，同时又不会增加对肩胛盂部件的扭矩或剪切力。
我们前瞻性地随访了 42 例因肩袖缺损而接受骨性增大偏心反肩关节置换的患者。从肱骨头上取下的自体松质骨圆柱被放置在研磨后的肩胛盂表面和基板之间。使用加长的中央钉（25 毫米）和四颗螺钉实现移植物和基板固定。术后至少 2 年，患者接受临床、影像学和 CT 评估。
在 42 例患者中，有 98%（41/42）的患者完全融合，1 例部分融合。术后平均 28 个月，未观察到移植物吸收、肩胛盂松动或术后不稳定。下肩胛切迹发生在 19%（42 例中有 8 例）。绝对 Constant-Murley 评分从 31 分提高到 67 分。36 例（86%）患者能够充分内旋以触及骶骨后面。
反肩关节置换时在肩胛盂表面进行植骨可有效形成长柄肩胛骨，从而实现假体外侧化的优势。骨性增大偏心反肩关节置换术后下肩胛切迹发生率低、肩关节旋转改善、假体无不稳定、肩部轮廓改善。与金属外侧化不同，骨性外侧化的优势在于保持假体旋转中心位于假体-骨界面，从而使肩胛盂部件的扭矩最小化。
IV 级，治疗研究。有关证据水平的完整描述，请参见作者指南。
