Department of Orthopaedics, Qilu Hospital of Shandong University, No.107 Wenhua West Road, Jinan, 250012, Shandong Province, China.
BMC Musculoskelet Disord. 2022 Jun 2;23(1):525. doi: 10.1186/s12891-022-05479-3.
The humerus fracture is one of the most commonly occurring fractures. In this research, we attempted to evaluate and compare the extent of malrotation and biomechanical environment after surgical treatment of humeral shaft fractures.
A finite element (FE) model of the shoulder was built based on Computed Tomography (CT) data of a patient with a humeral shaft fracture. The muscle group around the shoulder joint was simulated by spring elements. The changes of shoulder stresses under rotation were analyzed. The biomechanics of the normal shoulder and postoperative malrotation of the humeral shaft was analyzed and compared.
During rotations, the maximum stress was centered in the posterosuperior part of the glenoid for the normal shoulder. The von Mises shear stresses were 4.40 MPa and 4.89 MPa at 40° of internal and external rotations, respectively. For internal rotation deformity, the shear contact forces were 7-9 times higher for the shoulder internally rotated 40° than for the normal one. For external rotation deformity, the shear contact forces were about 3-5 times higher for the shoulder with 40° external rotation than the normal one.
Postoperative malrotation of humeral shaft fracture induced the changes of the biomechanical environment of the shoulders. The peak degree of malrotation was correlated with increased stresses of shoulders, which could be paid attention to in humeral shaft fracture treatment. We hoped to provide information about the biomechanical environment of humeral malrotation.
肱骨骨折是最常见的骨折之一。在这项研究中，我们试图评估和比较肱骨骨折手术后的旋转畸形程度和生物力学环境。
基于肱骨骨折患者的 CT 数据，构建了肩关节的有限元（FE）模型。用弹簧元素模拟肩关节周围的肌肉群。分析了旋转过程中肩关节应力的变化。分析和比较了正常肩关节和术后肱骨旋转畸形的生物力学。
在旋转过程中，正常肩关节的最大应力集中在关节盂的后上方。内、外旋 40°时，von Mises 剪切应力分别为 4.40 MPa 和 4.89 MPa。对于内旋畸形，内旋 40°的肩关节的剪切接触力比正常肩关节高 7-9 倍。对于外旋畸形，外旋 40°的肩关节的剪切接触力比正常肩关节高 3-5 倍。
肱骨骨折术后旋转畸形改变了肩关节的生物力学环境。旋转畸形的峰值程度与肩关节应力的增加有关，这在肱骨骨折治疗中值得关注。我们希望提供有关肱骨旋转畸形生物力学环境的信息。
