Tang J B, Ryu J, Omokawa S, Han J, Kish V
Department of Orthopedics, Health Sciences Center, West Virginia University, Morgantown, USA.
J Hand Surg Am. 1999 Jan;24(1):121-32. doi: 10.1053/jhsu.1999.jhsu24a0121.
We conducted a biomechanical study of changes in parameters of wrist motor tendons in fractures of the distal radius in 7 cadaveric extremities. Extra-articular distal radius fractures were simulated by distal radius osteotomy and fracture angulation was maintained by external fixators. Eight positions of the distal radius fractures were studied: dorsal angulation of 10 degrees, 20 degrees, 30 degrees, and 40 degrees and radial angulation of 5 degrees, 10 degrees, 15 degrees, and 20 degrees. Dorsal and radial angulation of the fractures were measured with respect to the shaft of the radius. Excursions of 5 principal wrist motor tendons extensor carpi radialis longus, extensor carpi radialis brevis, extensor carpi ulnaris, flexor carpi radialis, and flexor carpi ulnaris were recorded simultaneously with wrist joint angulation using a computer-assisted recording system. Data were collected from intact wrists and from wrists with fractures at each of 8 positions of angulation during wrist flexion and extension and radical and ulnar deviation. Moment arm of the wrist motor tendons was derived from tendon excursion and joint angulation. The results demonstrated that excursions and moment arms of principal wrist motor tendons are significantly affected by dorsal and radial angulation of distal radius fractures. Amplitude of changes in moment arms increased as the deformities became more severe. Statistical analysis revealed that dorsal angulation of 10 degrees or more significantly affected moment arms of all the prime wrist motors. Dorsal angulation of 30 degrees or 40 degrees changed the moment arms greatly. Radial angulation of 5 degrees did not affect moment arms of the tendons and angulation over 10 degrees had a statistically significant effect on the tendons. We conclude that deformities of distal radius fractures have a significant influence on the biomechanics of the wrist motors.
我们对7具尸体上肢桡骨远端骨折时腕部运动肌腱参数的变化进行了生物力学研究。通过桡骨远端截骨模拟关节外桡骨远端骨折，并用外固定器维持骨折成角。研究了桡骨远端骨折的8种位置：背侧成角10度、20度、30度和40度，以及桡侧成角5度、10度、15度和20度。骨折的背侧和桡侧成角是相对于桡骨干进行测量的。使用计算机辅助记录系统，在腕关节成角的同时，同步记录5条主要腕部运动肌腱（桡侧腕长伸肌、桡侧腕短伸肌、尺侧腕伸肌、桡侧腕屈肌和尺侧腕屈肌）的位移。在腕关节屈伸以及桡偏和尺偏过程中，从完整的腕部以及处于8种成角位置中每种位置的骨折腕部收集数据。腕部运动肌腱的力臂由肌腱位移和关节成角得出。结果表明，桡骨远端骨折的背侧和桡侧成角显著影响主要腕部运动肌腱的位移和力臂。随着畸形变得更加严重，力臂变化的幅度增大。统计分析显示，10度或更大的背侧成角显著影响所有主要腕部运动肌腱的力臂。30度或40度的背侧成角使力臂发生很大变化。5度的桡侧成角不影响肌腱的力臂，而10度以上的成角对肌腱有统计学上的显著影响。我们得出结论，桡骨远端骨折的畸形对腕部运动肌腱的生物力学有显著影响。
