Holy Cross Orthopedic Institute, Fort Lauderdale, FL, USA.
Department of Orthopedic Surgery, Larkin Community Hospital, South Miami, FL, USA.
J Shoulder Elbow Surg. 2024 May;33(5):1150-1156. doi: 10.1016/j.jse.2023.09.035. Epub 2023 Nov 7.
Acromion and scapular spine fractures (ASFs) following reverse total shoulder arthroplasty (RSA) have been reported at a rate of 3.9%. The location of the fracture has been shown to be an important factor in determining the outcomes of nonoperative treatment, with medial fractures having worse outcomes than lateral fractures. As the debate between operative and nonoperative treatment continues, a more precise understanding of the location of the fracture is necessary for effective management. The purpose of this study was to use 3-dimensional computed tomography (CT) reconstruction to characterize the exact location of ASFs after RSA.
A retrospective review of 2 separate institutional shoulder and elbow repositories was performed. Patients with post-RSA ASFs documented by post-fracture CT scans were included. The query identified 48 patients who sustained postoperative ASFs after RSA between July 2008 and September 2021. CT scans of patients with ASFs were segmented using Mimics software. Eight patients were excluded because of poor image quality. Each bone model was manipulated using 3-Matic Medical software to align the individual scapula with an idealized bone model to create a view of scapular fracture locations on a normalized bone model. This model was used to classify the fractures using the modified Levy classification.
The study cohort consisted of 40 patients with a diagnosis of postoperative ASF after RSA. The median age at the time of surgery was 76 years (interquartile range, 73-79 years). The cohort comprised 32 women (80%) and 8 men (20%), with a median body mass index of 27.8. Only 10 patients (25%) had a previous diagnosis of osteoporosis and 6 (13%) had a diagnosis of inflammatory arthritis; 53% of patients underwent RSA owing to rotator cuff tear arthropathy. The distribution of fracture locations was similar within the cohort. However, lateral fractures were slightly more prevalent. The most common fracture location was the type I zone, with 12 fracture lines (29%). There were 11 fracture lines (26%) in the type IIa zone, 10 (23%) in the type IIb zone, 0 in the type IIc zone, and 9 (21%) in the type III zone.
ASFs after RSA occur in 4 predictable clusters. No fractures appeared to distinctly cluster in the type IIc zone, which may not represent a true fracture zone. Understanding the distribution of these fractures will help to enable the future design of implants and devices to stabilize the fractures that require fixation.
反式全肩关节置换术后（RSA）发生肩峰和肩胛脊柱骨折（ASFs）的比例为 3.9%。骨折的位置已被证明是影响非手术治疗结果的重要因素，内侧骨折的结果比外侧骨折差。随着手术和非手术治疗之间的争论继续，对骨折位置的更精确理解对于有效的管理是必要的。本研究的目的是使用三维计算机断层扫描（CT）重建来描述 RSA 后 ASFs 的精确位置。
对两个独立的机构肩部和肘部存储库进行了回顾性审查。包括通过术后骨折 CT 扫描记录的 RSA 后 ASFs 的患者。查询确定了 2008 年 7 月至 2021 年 9 月期间 RSA 术后发生术后 ASFs 的 48 名患者。使用 Mimics 软件对 ASFs 患者的 CT 扫描进行分割。由于图像质量差，排除了 8 名患者。使用 3-Matic Medical 软件对每个骨骼模型进行操作，以使个体肩胛骨与理想骨骼模型对齐，以在归一化骨骼模型上创建肩胛骨骨折位置视图。该模型用于使用改良 Levy 分类法对骨折进行分类。
研究队列包括 40 名 RSA 术后诊断为术后 ASF 的患者。手术时的中位年龄为 76 岁（四分位距，73-79 岁）。该队列包括 32 名女性（80%）和 8 名男性（20%），中位体重指数为 27.8。仅有 10 名患者（25%）有骨质疏松症的既往诊断，6 名（13%）有炎症性关节炎的诊断；53%的患者因肩袖撕裂性关节炎而行 RSA。骨折部位的分布在队列内相似。然而，外侧骨折略为常见。最常见的骨折部位是 I 型区，有 12 条骨折线（29%）。IIa 区有 11 条骨折线（26%），IIb 区有 10 条（23%），IIc 区无骨折线，III 区有 9 条（21%）。
RSA 后发生的 ASFs 出现在 4 个可预测的集群中。没有明显的骨折聚集在 IIc 区，这可能不是真正的骨折区。了解这些骨折的分布情况将有助于未来设计固定所需骨折的植入物和装置。
