Zenker Martin, Shamsollahi Javad, Galm André, Hoyen Harry A, Jiang Chunyan, Lambert Simon, Nijs Stefaan, Jaeger Martin
R&D Department, DePuy Synthes, Zuchwil, Switzerland.
Department of Orthopaedic Surgery, MetroHealth Medical Center, Case Western Reserve University, Cleveland, OH, USA.
SAGE Open Med. 2022 Apr 21;10:20503121221091395. doi: 10.1177/20503121221091395. eCollection 2022.
Dislocations and periarticular fractures of the acromioclavicular joint are common injuries of the shoulder girdle. When surgical intervention is indicated, subacromial support is one option to restore the alignment between scapula and the distal/lateral clavicle. Devices used for subacromial support rely on a form of subacromial 'hook'. The shape, inclination and orientation of which is often mismatched to the anatomy of the inferior surface of the acromion, which may lead to painful acromial osteolysis and rotator cuff abrasion causing impingement. The primary goal of this study was to characterize the geometrical parameters of the acromion and distal clavicle, and their orientation at the acromioclavicular joint.
Computed tomography scans of 120 shoulders were converted into digital three-dimensional models. Measurements of the acromion inclination and acromion width relative to the torsional angle as well as the clavicle depth were taken. A numerical optimization of the anatomical parameters (including torsional and inclination angles, height and width) was performed to find the combination of those parameters with the lowest interpatient variability.
The mean clavicle depth was found to be 11.1 mm. The mean acromion width was 27 mm. The combination of torsional and inclination angles with lowest interpatient variability was found at 80° and 16°, respectively.
There is a high interpatient variability in the morphology of the inferior surface of the acromion. Subacromial support using a 'hook' can be optimized for contact surface area, which should lead to fewer complications after the restoration of acromioclavicular orientation using acromial support strategies.
肩锁关节脱位及关节周围骨折是肩胛带常见损伤。当需要手术干预时，肩峰下支撑是恢复肩胛骨与锁骨远端/外侧对线的一种选择。用于肩峰下支撑的装置依赖于一种肩峰下“钩”的形式。其形状、倾斜度和方向往往与肩峰下表面的解剖结构不匹配，这可能导致疼痛性肩峰骨质溶解和肩袖磨损，从而引起撞击。本研究的主要目的是描述肩峰和锁骨远端的几何参数及其在肩锁关节处的方向。
对120个肩部的计算机断层扫描转换为数字三维模型。测量肩峰倾斜度、相对于扭转角的肩峰宽度以及锁骨深度。对解剖参数（包括扭转角和倾斜角、高度和宽度）进行数值优化，以找到患者间变异性最低的参数组合。
发现锁骨平均深度为11.1毫米。肩峰平均宽度为27毫米。发现患者间变异性最低的扭转角和倾斜角组合分别为80°和16°。
肩峰下表面形态在患者间存在高度变异性。使用“钩”的肩峰下支撑可针对接触表面积进行优化，这在采用肩峰支撑策略恢复肩锁关节方向后应能减少并发症。
