Load transmission through the wrist in the extended position
Load transmission through the wrist in the extended position
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DOI：
10.1016/j.jhsa.2007.10.018
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发表时间：
2008-02-01
影响因子：
1.9
通讯作者：
Genda, Eiichi
中科院分区：
文献类型：
--
作者：
Majima, Masataka;Horii, Emiko;Genda, Eiichi
目的腕关节在伸展位置承受极高的压缩负荷，但该区域的病理解剖尚不清楚。本研究的目的是分析腕关节最大伸展位的力传递，以阐明腕关节损伤的病理机制。方法对7名正常受试者分别拍摄两组腕关节CT图像：一组为中立位，另一组为最大伸位。采用三维刚体弹簧模型分析了腕关节的应力分布。手腕关节是由计算机断层扫描图像构建的。外力作用于中立位的5个掌骨和伸展位的手掌。结果腕舟窝力传递率由中立位的52%增加到伸直位的62%(p<；.05)，月骨窝力传递率由42%降至36%。在腕中关节，对舟状骨的作用力从60%显著增加到69%(p<；0.05)。伸展位腕腕关节的受力分布向月牙窝中心和舟骨窝背间脊方向移动。放射状关节面背侧脊作为新的接触区出现。伸位时掌侧固有韧带和屈肌支持带张力明显增加。结论伸位时的力传递呈放射状移位，集中在舟状骨。我们可以看到弯曲力是如何导致舟骨骨折的，而力集中在桡骨表面可能会导致关节内骨折，这与Melone提出的骨折模式是一致的。掌侧固有韧带似乎是维持腕弓处于俯卧位的关键。我们的理论分析可以很好地解释手腕损伤的几种模式。
Purpose The wrist is subjected to extremely high compressive loads in the extended position, but pathoanatomy of this region remains unclear. The purpose of this study was to analyze force transmission in the maximum extended position to clarify the pathomechanics of wrist injury.Methods Two sets of computed tomography images of wrist joints were obtained for 7 normal subjects: one set in neutral position and the other set in maximum extension. A three-dimensional rigid body spring model was used to analyze stress distributions through the wrist joint. The wrist joint was constructed from computed tomography images. External force was applied to the 5 metacarpals in neutral position and to the palm in extended position. Force transmissions through the carpus and ligament tension in extended position were compared with those in neutral position, and farce distributions were compared in each position.Results Force transmission ratio on the scaphoid fossa significantly increased from 52% in neutral to 62% in extension (p < .05), whereas the ratio through the lunate fossa decreased from 42% to 36%. In the midcarpal joint, force to the scaphaid significantly increased from 60% to 69% (p < .05). Force distributions of the radiocarpal joint in the extended position moved on the center of the lunate fossa and interfossal ridge of the scaphaid fossa. The dorsal ridge of the radial articular surface appeared as the new contact area. Tension in 3 palmar intrinsic ligaments and the flexor retinaculum greatly increased in the extended position.Condusions Force transmission in the extended position shifted radially, concentrating at the scaphoid. We could show how bending force causes scaphoid fracture and concentration of force on the radius surface might cause intra-articular fracture coinciding with the fracture pattern introduced by Melone. The palmar intrinsic ligaments appear key to maintaining the carpal arch in push-up position. Our theoretical analysis could well explain several patterns of wrist injuries.