M. Ayvaz, R. M. Cetik, S. Bakircioglu, A. M. Tokgozoglu, Hacettepe University Hospitals by the Hacettepe University Faculty of Medicine, Department of Orthopedics and Traumatology Musculoskeletal Oncology Group, Ankara, Turkey.
Clin Orthop Relat Res. 2020 Nov;478(11):2585-2595. doi: 10.1097/CORR.0000000000001245.
The treatment of proximal humerus tumors with endoprostheses is associated with a high risk of implant-related surgical complications. Because of extensive soft-tissue resection and muscular detachment during surgery, instability is the most common serious complication. A reverse total shoulder arthroplasty with a highly constrained design is one option to mitigate instability, but few studies have reported the results of this prosthesis for proximal humerus tumor resections.
QUESTIONS/PURPOSES: (1) What are the short-term functional results of the constrained reverse total shoulder prosthesis in terms of Musculoskeletal Tumor Society (MSTS), DASH, and Constant-Murley scores and ROM values? (2) What is the frequency of revision, using a competing-risks estimator to assess implant survival, and what were the causes of the revisions that occurred? (3) What proportion of patients experienced dislocations at short-term follow-up?
Between January 2014 and June 2017, we treated 55 patients with proximal humeral resections and reconstructions for malignant tumors. Of those, 33% (18) of patients were treated with the constrained, reverse total shoulder arthroplasty implant under study here. During that period, no other constrained reverse total shoulder implant was used; however, 13% (seven) of patients were treated with conventional (unconstrained) reverse total shoulder implants, 27% (15) had hemiarthroplasties, 15% (eight) of patients had biologic reconstructions with auto- or allografts and 13% (seven) underwent amputation. During the period in question, our general indications for use of the constrained device under study here were resection of the deltoid muscle/axillary nerve or the deltoid insertion on the humerus due to tumor invasion, or extensive rotator cuff and surrounding soft tissue resection that might result in shoulder instability. During this period, these indications were adhered to consistently. Four of 18 patients treated with the study implant died (three died with the implant intact) and none were lost to follow-up before 2 years, leaving 14 patients (seven women and seven men) for study at a median (range) follow-up of 35 months (25 to 65). Two authors evaluated the clinical and functional status of each patient with ROM (flexion, extension, internal and external rotation, abduction, and adduction) and MSTS, (range 0% to 100%), Constant-Murley (range 0% to 100%), and DASH (range 0 points to 100 points) scores. For the MSTS and Constant-Murley scores, higher percentage scores mean better functional outcome; and for the DASH score, a higher score means more severe disability. Radiographs were obtained at each visit and were used to look for signs of loosening, which we defined as progressive radiolucencies between visits, prosthetic component migration, and fragmentation/fracture of the cement. The Sirveaux classification was used to determine scapular notching. A competing risks analysis with 95% confidence intervals was performed to estimate the cumulative incidence of revision surgery, which we defined as any reoperation in which the implant was removed or changed for any reason, with patient mortality as a competing event.
At the most recent follow-up, the median (range) MSTS score was 78% (50 to 90), the DASH score was 20 (8 to 65), and the Constant-Murley score was 53% (26 to 83). The median ROM was 75° in forward flexion (40 to 160), 78° in abduction (30 to 150), 35° in internal rotation (10 to 80), and 33° in external rotation (0 to 55). Postoperatively, two of 14 patients underwent or were supposed to undergo revision surgery, and the cumulative incidence of revision surgery was 18% for both 30 and 48 months (95% CI 2 to 45). During the study period, no patients reported instability, and no dislocations occurred.
Our findings are concerning because the revision risk with this constrained reverse total shoulder implant was higher than has been reported by others for other proximal humerus prostheses. The highly constrained design that helps prevent instability might also transmit increased stresses to the humeral component-bone interface, therefore making it susceptible to loosening. We believe that any other implant with a similar degree of constraint will have the same problem, and changing the indications for patient selection may not solve this issue. These theories need to be tested biomechanically, but our desire is to warn surgeons that while trying to prevent instability, one might trade one complication (instability) for another: aseptic loosening.
Level IV, therapeutic study.
肱骨近端肿瘤的假体治疗与假体相关的手术并发症风险较高。由于手术过程中广泛的软组织切除和肌肉分离，不稳定是最常见的严重并发症。使用高度约束的反向全肩关节置换术是减轻不稳定的一种选择，但很少有研究报告这种假体用于肱骨近端肿瘤切除的结果。
问题/目的：（1）在肌肉骨骼肿瘤学会（MSTS）、DASH 和 Constant-Murley 评分和 ROM 值方面，受限反向全肩关节假体的短期功能结果如何？（2）使用竞争风险估计器评估假体存活率，以及哪些是导致翻修的原因，翻修的频率是多少？（3）在短期随访中，有多少比例的患者发生脱位？
2014 年 1 月至 2017 年 6 月，我们治疗了 55 例肱骨近端恶性肿瘤切除和重建患者。其中，33%（18 例）的患者接受了研究中使用的受限、反向全肩关节假体治疗。在此期间，未使用其他受限反向全肩关节假体；然而，13%（7 例）的患者接受了常规（非约束）反向全肩关节假体治疗，27%（15 例）接受了半肩关节置换，15%（8 例）接受了生物重建，自体或同种异体移植物，13%（7 例）接受了截肢。在研究期间，我们使用研究中受限装置的一般适应证是由于肿瘤侵犯切除三角肌/腋神经或肱骨三角肌插入部，或广泛切除肩袖和周围软组织，可能导致肩关节不稳定。在此期间，始终坚持这些适应证。18 例接受研究植入物治疗的患者中有 4 例死亡（3 例植入物完整死亡），在 2 年之前没有患者失访，14 例患者（7 名女性和 7 名男性）接受了研究随访，中位（范围）随访时间为 35 个月（25 至 65）。两名作者使用 ROM（屈曲、伸展、内旋、外旋、外展和内收）和 MSTS（范围 0%至 100%）、Constant-Murley（范围 0%至 100%）和 DASH（范围 0 分至 100 分）评分评估每位患者的临床和功能状态。对于 MSTS 和 Constant-Murley 评分，较高的百分比表示更好的功能结果；对于 DASH 评分，较高的分数表示更严重的残疾。每次就诊时都获得 X 线片，并用于寻找松动的迹象，我们将其定义为随访期间逐渐出现的透光性、假体部件迁移和水泥的碎裂/骨折。使用 Sirveaux 分类法确定肩胛切迹。使用具有 95%置信区间的竞争风险分析来估计翻修手术的累积发生率，我们将其定义为任何因任何原因移除或改变植入物的再手术，患者死亡为竞争事件。
在最近的随访中，MSTS 评分的中位数（范围）为 78%（50 至 90），DASH 评分为 20（8 至 65），Constant-Murley 评分为 53%（26 至 83）。ROM 的中位数为前屈 75°（40 至 160），外展 78°（30 至 150），内旋 35°（10 至 80），外旋 33°（0 至 55）。术后，14 例患者中有 2 例或预计有 2 例需要进行翻修手术，翻修手术的累积发生率在 30 个月和 48 个月时均为 18%（95%CI 2%至 45%）。在研究期间，没有患者报告不稳定，也没有发生脱位。
我们的发现令人担忧，因为与其他肱骨近端假体相比，这种受限反向全肩关节假体的翻修风险更高。有助于防止不稳定的高度约束设计也可能使肱骨组件-骨界面承受更大的应力，从而使其易于松动。我们认为，任何具有类似约束程度的其他植入物都将存在同样的问题，改变患者选择的适应证可能无法解决这个问题。这些理论需要进行生物力学测试，但我们希望警告外科医生，在试图防止不稳定的同时，可能会用另一种并发症（不稳定）来换取另一种并发症：无菌性松动。
IV 级，治疗性研究。
