Bu Jianli, Patterson Rita M, Morris Randal, Yang JinPing, Viegas Steven F
Third Military Medical University, Heping (Peace) Hospital, Shijiazhuang, China.
J Hand Surg Am. 2006 Dec;31(10):1594-600. doi: 10.1016/j.jhsa.2006.09.004.
To assess load changes in the wrist and forearm resulting from surgically-induced radial shortening in wrists with inherent differences in ulnar variance.
Eleven fresh cadaver upper extremities, 4 with ulnar-plus variance of 2 mm or greater and 7 with ulnar-minus variance of 2 mm or greater were used. The radius and ulna of each specimen were instrumented with load cells, a 15-mm segment of the radius was resected and replaced with aluminum blocks of various sizes, and the specimens were loaded with 143 N (32 lb) at 1-mm differences of radial length. The load distribution between the radius and ulna was measured.
The load distribution in the specimens with an ulnar-plus variance averaged 69% through the radius and 31% through the ulna. In the wrists with ulnar-minus variance, the load distribution averaged 94% through the radius and 6% through the ulna. The mean force in the ulna increased and the mean force in the radius decreased with incremental shortening of the distal end of the radius. The mean force through the ulna in the ulnar-plus-variance group was always higher than that of the ulnar-minus-variance group. When compared not by the number of millimeters of radial shortening but by the adjusted ulnar variance, there was no difference between the ulnar-plus-variance and the ulnar-minus-variance groups.
Wrists with ulnar-minus variance could accommodate radial shortening without as much increase in the ulna load as wrists with ulnar-plus variance. The clinical relevance is that a patient with an ulnar-minus variance may accommodate more radial shortening after a wrist fracture without developing an ulnar impaction syndrome than a patient with an ulnar-plus-variant wrist.
评估在尺骨变异存在固有差异的手腕中，手术导致桡骨缩短所引起的手腕和前臂负荷变化。
使用11个新鲜尸体上肢，其中4个尺骨正变异为2毫米或更大，7个尺骨负变异为2毫米或更大。每个标本的桡骨和尺骨都安装了测力传感器，切除15毫米的桡骨段并用不同尺寸的铝块替换，然后在桡骨长度相差1毫米的情况下对标本施加143牛（32磅）的负荷。测量桡骨和尺骨之间的负荷分布。
尺骨正变异标本的负荷分布平均通过桡骨为69%，通过尺骨为31%。在尺骨负变异的手腕中，负荷分布平均通过桡骨为94%，通过尺骨为6%。随着桡骨远端逐渐缩短，尺骨的平均力增加，桡骨的平均力降低。尺骨正变异组中通过尺骨的平均力始终高于尺骨负变异组。当不是按桡骨缩短的毫米数而是按调整后的尺骨变异进行比较时，尺骨正变异组和尺骨负变异组之间没有差异。
与尺骨正变异的手腕相比，尺骨负变异的手腕能够适应桡骨缩短，而尺骨负荷增加幅度较小。临床意义在于，与尺骨正变异手腕的患者相比，尺骨负变异的患者在手腕骨折后可能能够适应更多的桡骨缩短而不发生尺骨撞击综合征。
