Department of Bioengineering, Imperial College London, London, UK.
Department of Trauma and Orthopaedics, Imperial College Healthcare NHS Trust, London, UK.
Bone Joint J. 2019 Jan;101-B(1):68-74. doi: 10.1302/0301-620X.101B1.BJJ-2018-0974.R1.
Patients with recurrent anterior dislocation of the shoulder commonly have an anterior osseous defect of the glenoid. Once the defect reaches a critical size, stability may be restored by bone grafting. The critical size of this defect under non-physiological loading conditions has previously been identified as 20% of the length of the glenoid. As the stability of the shoulder is load-dependent, with higher joint forces leading to a loss of stability, the aim of this study was to determine the critical size of an osseous defect that leads to further anterior instability of the shoulder under physiological loading despite a Bankart repair.
Two finite element (FE) models were used to determine the risk of dislocation of the shoulder during 30 activities of daily living (ADLs) for the intact glenoid and after creating anterior osseous defects of increasing magnitudes. A Bankart repair was simulated for each size of defect, and the shoulder was tested under loading conditions that replicate in vivo forces during these ADLs. The critical size of a defect was defined as the smallest osseous defect that leads to dislocation.
The FE models showed a high risk of dislocation during ADLs after a Bankart repair for anterior defects corresponding to 16% of the length of the glenoid.
This computational study suggests that bone grafting should be undertaken for an anterior osseous defect in the glenoid of more than 16% of its length rather than a solely soft-tissue procedure, in order to optimize stability by restoring the concavity of the glenoid.
复发性肩关节前脱位患者常存在肩胛盂前骨缺损。一旦缺损达到临界大小，通过植骨可恢复稳定性。先前已确定这种非生理负荷条件下的缺损临界大小为肩胛盂长度的 20%。由于肩关节的稳定性依赖于负荷，关节力较高会导致不稳定，因此本研究旨在确定在Bankart 修复后，在生理负荷下导致肩进一步前不稳定的骨缺损临界大小，尽管存在Bankart 修复。
使用两个有限元（FE）模型来确定在完整肩胛盂和在创建大小不断增加的前骨缺损后进行 30 项日常活动（ADL）时肩部脱位的风险。对每个大小的缺损模拟 Bankart 修复，并在模拟 ADL 期间体内力的负荷条件下测试肩部。将缺损的临界大小定义为导致脱位的最小骨缺损。
FE 模型显示，Bankart 修复后，肩胛盂前缺损对应于肩胛盂长度的 16%，在 ADL 期间发生脱位的风险很高。
这项计算研究表明，对于肩胛盂前骨缺损超过其长度的 16%，应进行植骨而不是单纯的软组织手术，以通过恢复肩胛盂的凹度来优化稳定性。
