腕动力学变化对四角融合术的影响

Effect of carpal kinetics on stability of four-corner arthrodesis

目的了解腕动力学的变化对四角融合术的影响,探讨融合术后如何改善腕功能。方法取12具新鲜尸体标本,在模拟四角融合术后作腕掌屈、背伸、尺偏、桡偏运动。运动前后拍摄腕关节正侧位片,测量头月角、桡月角、头月正位角、融合体高度与融合体宽度,并记录致克氏针弯曲的角度。结果腕掌屈至50°、背伸至40°时,各项指标运动前后的差异有统计学意义(P<0.01),腕尺偏至25°、桡偏至15°时,运动前后的差异有统计学意义(P<0.05)。结论影响四角融合体稳定性的临界角度为掌屈50°、背伸40°、尺偏25°、桡偏15°。四角融合术后,腕骨结构与动力学的改变及术后长时间外固定是术后腕关节活动范围部分丢失的原因。术后4周始在临界角度范围内早期锻炼是改善腕功能的有效方法。

Objective To observe the effect of carpal kinetics on stability of four-corner arthrodesis and to explore the strategy improving the range of motion （ROM） of wrist after four-corner arthrodesis. Methods After the simulated four-corner arthrodesis, 12 fresh cadaver forearms were mounted on the wrist motion simulator and wrist movement including flexion, extension, radial and ulnar deviation were simulated. The standard posteroanterior and lateral radiographs were taken for measuring the changes of capitolunate （CL） angle, radiolunate （RL） angle,capitolunate posteroanterior angle, the height and width of the fused four carpal bone bloc. The angles making K-wire curved were recorded as well. Results There were statistically significant differences between neutral position and the position in 50° flexion and 40° extension （P 〈 0.01 ）. The differences between neutral position and the position in 25° ulnar deviation and 15°radial deviation were of statistic significance （ P 〈 0.05）. Conclusion The safe range of motion to the stability of four-corner arthrodesis is less 50° flexion, 40° extension, 25° ulnar deviation, and 15° radial deviation. Loss of motion following four-corner arthrodesis arc partially attributed to the anatomic and kinetic changes as well as prolonged post-operative immobilization. The early exercise within the safe range of motion of wrist starting at the post-operative week four is recommended to improve wrist motion.