Department of Orthopaedic Surgery, Graduate School of Biomedical & Health Sciences, Hiroshima University, Japan.
Department of Orthopaedic Surgery, Graduate School of Biomedical & Health Sciences, Hiroshima University, Japan.
J Orthop Sci. 2024 Mar;29(2):521-528. doi: 10.1016/j.jos.2023.01.003. Epub 2023 Jan 27.
Stress shielding and osteolysis around the humeral stem after reverse shoulder arthroplasty causes loosening and periprosthetic fractures and reduces bone stock during revision surgery. In Japanese patients, who have relatively small bodies, different characteristics may exist regarding the occurrence of these changes compared with the characteristics of Westerners, who have relatively larger frames. The purpose of this multicenter study was to investigate the incidence and clarify the predictors of stress shielding and osteolysis in Japanese individuals who underwent reverse shoulder arthroplasty.
The occurrence of stress shielding and osteolysis was investigated in 135 shoulders that had undergone reverse shoulder arthroplasty at least 2 years prior in five Japanese hospitals. During post-surgical follow-up, which was conducted every 3 months, the locations of the stress shielding occurrences, such as cortical thinning and osteopenia (which primarily occurred in zones 1, 2, and 7, where 1 is the greater tuberosity and 7 is the calcar part), spot weld, and condensation lines, were recorded. Cases without any abnormal findings on radiographs obtained up to ≥2 years after surgery were regarded as having no abnormalities. Finally, the predictors of cortical thinning and proximal humeral osteolysis were assessed using univariate and multivariate regression analyses.
Cortical thinning and osteopenia occurred in 68 shoulders, a condensation line occurred in 37 shoulders, and spot weld occurred in 23 shoulders. In particular, greater tuberosity and calcar osteolysis occurred in 40 and 47 shoulders, respectively. Long stem, cementless stem, and a larger proximal filling ratio were independent predictors of cortical thinning and osteopenia, whereas a cementless stem, larger metaphysis diameter, and a larger proximal filling ratio were associated with proximal humeral osteolysis.
The predictors of stress shielding and osteolysis included the use of long stems, cementless stems, larger proximal filling ratios, and larger metaphysis diameters.
retrospective comparative study (Level III).
反肩置换术后肱骨柄周围的应力遮挡和骨溶解导致松动和假体周围骨折，并在翻修手术时减少骨量。在日本患者中，由于体型相对较小，与体型相对较大的西方人相比，这些变化的发生可能存在不同的特征。本多中心研究的目的是调查应力遮挡和骨溶解的发生率，并阐明日本接受反肩置换术患者的发生预测因素。
在日本的五家医院，对 135 例至少在 2 年前接受过反肩置换术的患者进行了术后随访，调查应力遮挡和骨溶解的发生情况。在术后每 3 个月的随访过程中，记录了应力遮挡的发生部位，如皮质变薄和骨质疏松（主要发生在 1 区、2 区和 7 区，其中 1 区是大结节，7 区是骨突）、点焊缝和冷凝线。术后至少 2 年的 X 线片未见任何异常发现的病例被认为无异常。最后，采用单变量和多变量回归分析评估皮质变薄和肱骨头近端骨溶解的预测因素。
68 例出现皮质变薄和骨质疏松，37 例出现冷凝线，23 例出现点焊缝。特别是大结节和骨突骨溶解分别发生在 40 例和 47 例。长柄、非骨水泥柄和较大的近端填充率是皮质变薄和骨质疏松的独立预测因素，而非骨水泥柄、较大的骨干直径和较大的近端填充率与肱骨头近端骨溶解相关。
应力遮挡和骨溶解的预测因素包括使用长柄、非骨水泥柄、较大的近端填充率和较大的骨干直径。
回顾性比较研究（III 级）。
