Daneshvarhashjin Nazanin, Debeer Philippe, Matthews Harold, Claes Peter, Verhaegen Filip, Scheys Lennart
Department of Development and Regeneration, Faculty of Medicine, Institute for Orthopaedic Research and Training (IORT), KU Leuven, Herestraat 49-bus 7003 68, 3000, Leuven, Belgium.
Division of Orthopaedics, University Hospitals Leuven, Leuven, Belgium.
Biomech Model Mechanobiol. 2025 Aug;24(4):1141-1153. doi: 10.1007/s10237-025-01947-6. Epub 2025 Jun 17.
Rotator cuff muscle (RCM) degeneration, bone morphology, and humeral head subluxation (HHS) are known risk factors for failure of anatomic total shoulder arthroplasty in patients with B-glenoid shoulder osteoarthritis. Yet, the understanding of RCM asymmetry in these patients remains an area of active investigation, including its relation with other risk factors. We therefore aimed to characterize the variability of RCM degeneration in B-glenoids and analyze its covariation with scapular morphology and HHS. First, computed tomography images were used to quantify 3D RCM degeneration, including muscle atrophy and fatty infiltration, in sixty B-glenoids referenced against twenty-five healthy controls. Next, the 3D scapular shape of B-glenoids was quantified using a previously published statistical shape model. Thirdly, 3D HHS was quantified. Using dedicated correlation analyses covariation patterns were modeled between each of these risk factors. Results indicated that RCM degeneration in B-glenoids is primarily characterized by fatty infiltration, without any sign of asymmetric impact on the anterior versus posterior RCM. However, B-glenoids with asymmetric bone loss were found to have more RCM atrophy and fatty infiltration of the infraspinatus. We identified four significant patterns of RCM degeneration and scapular shape, explaining 90.3% of their correlation. The primary mode indicates an association between combined posterior glenoid erosion and coracoid rotation with an increased infraspinatus' fatty infiltration. Interestingly, this mode was also positively correlated with posterior HHS (r = 0.46, P < 0.01). Identification of such patterns can improve the accuracy of musculoskeletal models in predicting postoperative implant failure risks.
肩袖肌（RCM）退变、骨形态以及肱骨头半脱位（HHS）是B型盂肱关节骨关节炎患者解剖型全肩关节置换术失败的已知风险因素。然而，对于这些患者中RCM不对称性的理解仍是一个活跃的研究领域，包括其与其他风险因素的关系。因此，我们旨在描述B型盂肱关节中RCM退变的变异性，并分析其与肩胛骨形态和HHS的协变关系。首先，使用计算机断层扫描图像对60例B型盂肱关节的三维RCM退变进行量化，包括肌肉萎缩和脂肪浸润，并以25例健康对照为参照。其次，使用先前发表的统计形状模型对B型盂肱关节的三维肩胛骨形状进行量化。第三，对三维HHS进行量化。通过专门的相关性分析，对这些风险因素之间的协变模式进行建模。结果表明，B型盂肱关节中的RCM退变主要表现为脂肪浸润，对前侧与后侧RCM没有任何不对称影响的迹象。然而，发现伴有不对称骨质流失的B型盂肱关节有更多的RCM萎缩和冈下肌脂肪浸润。我们确定了RCM退变和肩胛骨形状的四种显著模式，解释了它们相关性的90.3%。主要模式表明，盂肱关节后侧联合侵蚀和喙突旋转与冈下肌脂肪浸润增加之间存在关联。有趣的是，这种模式也与后侧HHS呈正相关（r = 0.46，P < 0.01）。识别这些模式可以提高肌肉骨骼模型预测术后植入物失败风险的准确性。
