Smith D K, Cooney W P, An K N, Linscheid R L, Chao E Y
Department of Orthopedics, Mayo Clinic/Mayo Foundation, Rochester, MN 55905.
J Hand Surg Am. 1989 Mar;14(2 Pt 1):283-91. doi: 10.1016/0363-5023(89)90022-1.
The kinematics of five fresh frozen wrist specimens were studied before and after a simulated scaphoid waist fracture. To determine the change in wrist motion and fracture site characteristics associated with an unstable wrist, the relative motion of each carpal bone was determined from the movement of implanted carpal markers on biplanar radiographs obtained in neutral and the four extreme wrist positions. The kinematics of the wrist in our specimens before the osteotomy were similar to previous studies. After the osteotomy, the proximal and distal segments of the scaphoid moved independently. The distal scaphoid assumed a relatively flexed stance and displayed increased motion. The proximal scaphoid fragment and lunate assumed a relatively extended stance and displayed less motion after the osteotomy. These kinematic abnormalities produced significant interfragmentary motion that would be expected to complicate normal fracture healing. The spontaneous collapse of the two scaphoid fragments produced a dorsal angulation or "humpback" deformity that simulated the clinical situation of displaced scaphoid nonunions. The scaphoid serves an important role maintaining normal alignment of the carpal bones and producing normal wrist motion.
在模拟舟状骨腰部骨折前后，对五个新鲜冷冻腕关节标本的运动学进行了研究。为了确定与腕关节不稳定相关的腕关节运动变化和骨折部位特征，通过在中立位和四个极端腕关节位置获得的双平面X线片上植入腕骨标记物的运动，确定了每块腕骨的相对运动。在截骨术前，我们标本中腕关节的运动学与先前的研究相似。截骨术后，舟状骨的近端和远端节段独立移动。舟状骨远端呈现相对屈曲姿势并显示运动增加。截骨术后，舟状骨近端碎片和月骨呈现相对伸展姿势并显示运动减少。这些运动学异常产生了显著的骨折块间运动，预计会使正常骨折愈合复杂化。两个舟状骨碎片的自发塌陷产生了背侧成角或“驼背”畸形，模拟了移位舟状骨不愈合的临床情况。舟状骨在维持腕骨正常排列和产生正常腕关节运动方面起着重要作用。
