Matsushita K, Nagao Y, Beppu M, Sasa M N, Ishii S, Miyoshi K, Tsai T M
Department of Orthopaedic Surgery, St. Marianna University School of Medicine, Kanagawa, Japan.
Nihon Seikeigeka Gakkai Zasshi. 1995 Jan;69(1):1-10.
The purpose of this study was to clarify the pathomechanics of dorsiflexed intercalated segmental instability (DISI) in a scaphoid fracture. Twenty two patients with a scaphoid fracture were used for the clinical study. DISI was recognized in 6 patients. There was no statistically significant difference between the DISI(+) group and the DISI(-) group in total ROM, or in grip strength. In the DISI(+) group, however, ROM shifted dorsally (p < 0.05). Clinical factors for DISI were as follows. (1) pseudoarthrosis without treatment: 2 cases; (2) bone union taking place in a humpbacked position: 3 cases; (3) resection of proximal fragment: 1 case. Two fresh cadavers were used for the experimental study. In one cadaver which received simple osteotomy of the scaphoid, DISI was not seen after 216,000 repeated wrist movements (15 times/min., 10 days). In the other cadaver which underwent a volar wedge osteotomy of the scaphoid, the proximal fragment of the scaphoid and the lunate dorsiflexed temporarily under axial compression force immediately after surgery. After 8 days (172,800 repeated movements), static DISI could be seen without axial compression force. These results suggested that a volar bone defect was important for DISI after a scaphoid fracture. When an axial compression force was added, both the proximal fragment of the scaphoid and the lunate could be dorsiflexed in proportion to the volar bone defect due to the linkage between the proximal fragment and the lunate. Loosening in the surrounding tissue occurred gradually during continuous wrist movement and static DISI was finally observed. Therefore, immediate and proper treatment should be recommended to prevent mal-union as well as non-union.
本研究的目的是阐明舟骨骨折时背伸型插入节段性不稳定（DISI）的病理力学机制。22例舟骨骨折患者纳入临床研究。其中6例患者出现DISI。DISI（+）组与DISI（-）组在总活动度或握力方面无统计学显著差异。然而，在DISI（+）组中，活动度向背侧偏移（p < 0.05）。DISI的临床因素如下：（1）未经治疗的假关节：2例；（2）在驼背位置发生骨愈合：3例；（3）近端骨折块切除：1例。使用两具新鲜尸体进行实验研究。在一具仅行舟骨截骨术的尸体中，经过216,000次重复腕关节活动（15次/分钟，共10天）后未出现DISI。在另一具接受舟骨掌侧楔形截骨术的尸体中，术后立即施加轴向压缩力时，舟骨近端骨折块和月骨暂时背伸。8天后（172,800次重复活动），在无轴向压缩力情况下可观察到静态DISI。这些结果表明，掌侧骨缺损对舟骨骨折后DISI的发生很重要。当施加轴向压缩力时，由于舟骨近端骨折块与月骨之间的连接，舟骨近端骨折块和月骨均可因掌侧骨缺损而按比例背伸。在持续的腕关节活动过程中，周围组织逐渐松弛，最终观察到静态DISI。因此，应建议立即进行适当治疗以预防畸形愈合和不愈合。
