Orthopaedic Biomechanics Laboratory, VA Long Beach Healthcare System, Long Beach, CA 90822, USA.
J Orthop Trauma. 2012 Oct;26(10):591-6. doi: 10.1097/BOT.0b013e31824135af.
The purpose of this study was to evaluate the influence of forearm rotation on failure patterns of the elbow under axial loads.
Fourteen upper extremities were resected mid-humerus and mounted on a custom apparatus, which allowed rotation of the ulna, radius, and humerus about a fixed wrist while loading in axial compression. Seven specimens were loaded to failure with the forearm in pronation and 7 in supination.
Six of the 7 elbows axially loaded in pronation resulted in fractures of the radial head and coronoid with posterior dislocation (terrible triad). Six of the 7 elbows loaded in supination dislocated without fracture. One of the 7 elbows tested in supination had a terrible triad-type elbow injury. Five of the 6 specimens with ulna external rotation had damage to the lateral ligaments; all 8 specimens with internal rotation had damage to the medial ligaments. There were no significant differences in biomechanical parameters between pronation and supination.
The forearm position during axial load was the primary determinant of fracture-dislocation pattern. When the forearm was pronated, a terrible triad injury pattern most often occurred. When the forearm was supinated, a dislocation without fracture most often occurred. In both forearm rotation positions, when the ulna internally rotated during failure, the medial structures were the first to be disrupted. When the ulna externally rotated, the lateral structures were the first to be disrupted. Understanding the pathomechanics of elbow dislocation may improve diagnosis and treatment of these injuries.
本研究旨在评估在轴向负荷下，前臂旋转对肘关节失败模式的影响。
14 个上肢标本自肱骨干中部离断，安装在特制的装置上，该装置允许尺骨、桡骨和肱骨围绕固定的腕关节旋转，同时在轴向压缩下加载。7 个标本在前旋位加载至失效，7 个标本在后旋位加载至失效。
在前旋位加载的 7 个肘关节中有 6 个导致桡骨头和冠状突骨折伴后脱位（恐怖三联征）。在后旋位加载的 7 个肘关节中有 6 个无骨折脱位。在后旋位加载的 7 个肘关节中有 1 个发生了恐怖三联征样的肘关节损伤。在有尺骨外旋的 6 个标本中有 5 个外侧韧带损伤；所有 8 个有尺骨内旋的标本均有内侧韧带损伤。在前旋和后旋位时，生物力学参数无显著差异。
轴向负荷时前臂的位置是决定骨折-脱位模式的主要因素。当前臂处于旋前位时，常发生恐怖三联征样损伤。当前臂处于旋后位时，常发生无骨折脱位。在前臂旋前和旋后两种旋转位置下，当发生失败时尺骨内旋，内侧结构首先被破坏。当尺骨外旋时，外侧结构首先被破坏。了解肘关节脱位的病理力学机制可能有助于改善这些损伤的诊断和治疗。
