Nishiwaki Masao, Nakamura Toshiyasu, Nagura Takeo, Toyama Yoshiaki, Ikegami Hiroyasu
Biomechanics Laboratory, Department of Orthopaedic Surgery, School of Medicine, Keio University, Shinjuku-ku, Tokyo, Japan.
J Hand Surg Am. 2008 Feb;33(2):198-205. doi: 10.1016/j.jhsa.2007.11.024.
The ulnar-shortening procedure has been successfully used to relieve ulnar impaction syndrome and may help in stabilizing the distal radioulnar joint (DRUJ) by increasing the tension within the triangular fibrocartilage complex. This procedure, however, may increase pressure at the DRUJ and possibly induce degenerative changes in the joint. This study aimed to examine the changes in pressure at the DRUJ by simulating the ulnar-shortening procedure in intact and torn states of the triangular fibrocartilage complex.
Seven fresh-frozen cadaver arms amputated at the midportion of the humerus were used. The ulna and humerus were affixed firmly to a custom mount that allowed 60 degrees forearm rotation. An external fixator was attached to the distal ulna, leaving a 10-mm space to allow progressive shortening. Pressure sensors were inserted in the DRUJ, and pressure distribution in the joint was recorded after every 1-mm shortening that was performed up to a maximum of 6 mm with or without the application of muscle load. These data were then compared with those obtained with the original length of the ulna in 3 joint positions: neutral, 60 degrees pronation, and 60 degrees supination. The tests were repeated after sectioning either the dorsal or the palmar portion of the radioulnar ligament (RUL) and finally after complete sectioning of the RUL.
The peak pressure at the DRUJ increased notably in the intact specimens during progressive ulnar shortening. Compared with the intact specimens, those with partial RUL sectioning exhibited a smaller increase in the peak pressure with ulnar shortening. Complete sectioning of the RUL at its attachment to the ulnar fovea resulted in even smaller increases.
The greater the amount of ulnar shortening, the higher is the peak pressure at the DRUJ. The amount of ulnar shortening should be carefully planned to avoid excessive pressure at the DRUJ.
尺骨短缩术已成功用于缓解尺骨撞击综合征，并且通过增加三角纤维软骨复合体内部的张力可能有助于稳定下尺桡关节（DRUJ）。然而，该手术可能会增加下尺桡关节处的压力，并可能诱发关节的退行性改变。本研究旨在通过模拟三角纤维软骨复合体完整和撕裂状态下的尺骨短缩术，来检查下尺桡关节处压力的变化。
使用7个在肱骨中部截断的新鲜冷冻尸体手臂。将尺骨和肱骨牢固地固定在一个定制的装置上，该装置允许前臂旋转60度。在尺骨远端连接一个外固定器，留出10毫米的空间以进行渐进性短缩。将压力传感器插入下尺桡关节，并在有或无肌肉负荷的情况下，每短缩1毫米（最大短缩6毫米）后记录关节内的压力分布。然后将这些数据与在3个关节位置（中立位、旋前60度和旋后60度）下尺骨原始长度时获得的数据进行比较。在切断尺桡韧带（RUL）的背侧或掌侧部分后以及最后完全切断RUL后重复这些测试。
在渐进性尺骨短缩过程中，完整标本中下尺桡关节处的峰值压力显著增加。与完整标本相比，部分切断RUL的标本在尺骨短缩时峰值压力的增加较小。在RUL附着于尺骨凹处完全切断RUL导致的压力增加更小。
尺骨短缩量越大，下尺桡关节处的峰值压力越高。应仔细规划尺骨短缩量，以避免下尺桡关节处出现过大压力。
