Department of Orthopaedics and Trauma Surgery, St. Josef Hospital, Ruhr University, Bochum, Germany.
Department of Sports Orthopaedics, St. Vinzenz Hospital, Düsseldorf, Germany.
Arch Orthop Trauma Surg. 2023 Feb;143(2):959-965. doi: 10.1007/s00402-022-04382-9. Epub 2022 Mar 28.
Coracoid fractures after arthroscopic treatment of acromioclavicular (AC) joint separations lead to poor clinical outcomes. In this study, different configurations of bone tunnels in the lateral clavicle and coracoid were examined concerning the amount of stress induced in the coracoid.
An authentic 3D finite element model of an ac joint was established. Three 2.4 mm bone tunnels were inserted in the lateral clavicle, which were situated above, medially and laterally of the coracoid. Then, two 2.4 mm bone tunnels were inserted in the latter, each simulating a proximal and a distal suture button position. Von Mises stress analyses were performed to evaluate the amount of stress caused in the coracoid process by the different configurations. Then, a clinical series of radiographs was examined, the placement of the clavicle drill hole was analyzed and the number of dangerous configurations was recorded.
The safest configuration was a proximal tunnel in the coracoid combined with a lateral bone tunnel in the clavicle, leading to an oblique traction at the coracoid. A distal bone tunnel in the coracoid and perpendicular traction as well as a proximal tunnel in the coracoid with medial traction caused the highest stresses. Anatomical placement of the clavicle drill hole does lead to configurations with smaller stresses.
The bone tunnel placement with the smallest amount of shear stresses was found when the traction of the suture button was directed slightly lateral, towards the AC joint. Anatomical placement of the clavicle drill hole alone was not sufficient in preventing dangerous configurations.
Controlled laboratory study.
关节镜治疗肩锁关节（AC）分离后喙突骨折会导致不良的临床结果。在这项研究中，研究了锁骨外侧和喙突不同的骨隧道构型，以检查其在喙突上引起的应力量。
建立了一个真实的 AC 关节的 3D 有限元模型。在锁骨外侧插入了三个 2.4mm 的骨隧道，它们位于喙突的上方、内侧和外侧。然后，在后者中插入了两个 2.4mm 的骨隧道，每个模拟一个近端和一个远端缝线纽扣位置。进行了 Von Mises 应力分析，以评估不同构型在喙突上引起的应力量。然后，检查了一系列临床 X 光片，分析了锁骨钻孔的位置，并记录了危险构型的数量。
最安全的构型是喙突内的近端隧道与锁骨外侧的骨隧道相结合，导致喙突的斜向牵引。喙突内的远端骨隧道和垂直牵引以及喙突内的近端隧道与内侧牵引会导致最高的应力。锁骨钻孔的解剖位置确实会导致应力较小的构型。
当缝线纽扣的牵引稍微向 AC 关节的外侧引导时，发现骨隧道的放置方式产生的剪切应力量最小。单独解剖位置的锁骨钻孔放置不足以防止危险构型。
对照实验室研究。
