Shoulder and Elbow Unit, Department of Orthopedic and Trauma Surgery, Hospital Clínico San Carlos, C/Martín Lagos, s/n., 28040, Madrid, Spain.
Department of Surgery, Facultad de Medicina, Universidad Complutense, Madrid, Spain.
Eur J Orthop Surg Traumatol. 2022 Dec;32(8):1525-1534. doi: 10.1007/s00590-021-03131-9. Epub 2021 Sep 30.
Improvement in reverse total shoulder arthroplasty (RTSA) prosthesis and technique has reduced the initially high complication and revision rates associated with this implant. However, instability continues to be a leading cause of reoperation after RTSA, being related in previous studies with medialized designs. The aim of this study was to determine the dislocation rate with the employment of two medialized modular systems of RTSA in our institution.
A retrospective review of two different modular systems of RTSA (SMR Modular Shoulder System and Delta XTEND Reverse Shoulder) was performed between 2009 and 2017 with a minimum 3-year follow-up. Baseline demographic, clinical (Constant, ASES and ROM), and radiographic data were collected. Characteristics of postoperative instability cases were also evaluated.
237 primary RTSA (41% SMR/59% Delta) and 34 revision RTSA (44% SMR/56% Delta) with a mean follow-up of 75.6 ± 5.2 months (79.2 SMR/86.3 Delta, p = .586) were included in the present study. Indications for primary RTSA were osteoarthritis, rotator cuff tear arthropathy and massive irreparable rotator cuff tear (64%), acute fracture (32%), and fracture sequelae (4%). Subscapularis tendon was always repaired in degenerative pathology and tuberosities reattached in traumatic cases. The mean age of the global series was 76.5 ± 5.3 years (75.8 SMR/78.6 Delta, p = .104) with a mean Constant/ASES score at final follow-up of 68.5 ± 4.3/72.9 ± 20.3 (71/68 SMR and 69/74 Delta, p = .653 and .642). Only 2 patients (one acute fracture and one fracture sequelae) suffered an early postoperative anterior dislocation (before 3 months) which represents a rate of .84% in primary cases and .73% including revision surgery. Closed reduction manoeuvres were not successful, and both patients required revision surgery. At the end follow-up, both were stable and had no further dislocations.
The dislocation rate after RTSA with the employment of two contemporary modular systems with a medialized centre of rotation is extremely low, especially when compared with the previously published series with the original Grammont design. Acute fracture and fracture sequelae were the main diagnoses associated with this instability. The reasons for the low dislocation rate are multifactorial, but the improvement in the baseplate position according to the more recent standards of "ideal position" and technical aspects such as subscapularis repair or tuberosity reattachment in fractures probably play an important role in this aspect.
反向全肩关节置换术（RTSA）假体和技术的改进降低了与该植入物相关的最初高并发症和翻修率。然而，不稳定仍然是 RTSA 后再次手术的主要原因，在前述研究中与中心化设计有关。本研究旨在确定我们机构中两种中心化模块化 RTSA 系统的脱位率。
对 2009 年至 2017 年期间使用两种不同模块化 RTSA 系统（SMR 模块化肩部系统和 Delta XTEND 反向肩部）的患者进行回顾性分析，随访时间至少为 3 年。收集基线人口统计学、临床（Constant、ASES 和 ROM）和影像学数据。还评估了术后不稳定病例的特征。
本研究共纳入 237 例原发性 RTSA（41% SMR/59% Delta）和 34 例翻修 RTSA（44% SMR/56% Delta），平均随访 75.6±5.2 个月（79.2 SMR/86.3 Delta，p=0.586）。原发性 RTSA 的适应证为骨关节炎、肩袖撕裂性关节炎和巨大不可修复的肩袖撕裂（64%）、急性骨折（32%）和骨折后遗症（4%）。在退行性病变中总是修复肩胛下肌腱，在创伤性病例中重新附着结节。整个系列的平均年龄为 76.5±5.3 岁（75.8 SMR/78.6 Delta，p=0.104），最终随访时平均 Constant/ASES 评分为 68.5±4.3/72.9±20.3（71/68 SMR 和 69/74 Delta，p=0.653 和 0.642）。仅 2 例患者（1 例急性骨折，1 例骨折后遗症）发生术后早期前脱位（3 个月内），原发性病例的发生率为 0.84%，包括翻修手术为 0.73%。闭合复位手法不成功，均需行翻修手术。末次随访时，均稳定，无再脱位。
使用两种具有中心化旋转中心的现代模块化系统进行 RTSA 的脱位率极低，尤其是与先前发表的具有原始 Grammont 设计的系列相比。急性骨折和骨折后遗症是与这种不稳定相关的主要诊断。低脱位率的原因是多方面的，但根据“理想位置”的最新标准改善基板位置以及肩胛下肌修复或骨折时结节再附着等技术方面可能在此方面发挥重要作用。
