Harley Brian J, Pereria Mario L, Werner Frederick W, Kinney Daniel A, Sutton Levi G
Department of Orthopedic Surgery, SUNY Upstate Medical University, Syracuse, NY.
Department of Orthopedic Surgery, SUNY Upstate Medical University, Syracuse, NY.
J Hand Surg Am. 2015 Feb;40(2):211-6. doi: 10.1016/j.jhsa.2014.10.001. Epub 2014 Nov 15.
To better define normal wrist joint forces during wrist motion and forearm motion at specific wrist and forearm positions and to see if there is a relationship between these forces and the amount of ulnar variance. A secondary purpose was to determine the relationship between the thickness of the articular disk of the triangular fibrocartilage complex and the amount of force transmitted through the distal ulna.
Multi-axis load cells were attached to the distal radius and ulna of 9 fresh cadaver forearms. The axial radial and ulnar compressive forces were recorded while each wrist was moved through wrist and forearm motions using a modified wrist joint simulator. During each motion, the tendon forces required to cause each motion were recorded. The ulnar variance and triangular fibrocartilage complex articular disc thickness were measured.
The axial force through the distal ulna and the wrist extensor forces were greatest with the forearm in pronation. No relationship was found between the amount of force through the distal ulna and the amount of ulnar variance. A strong inverse relationship was found between the triangular fibrocartilage complex thickness and the ulnar variance.
Wrists with positive ulnar variance have generally been thought to transmit greater loads across the distal ulna, which has been felt to predispose these wrists to the development of ulnar impaction. The results of this study appear to show that all wrists have similar loading across the distal ulna regardless of ulnar variance. By comparison, pronation relatively increases loading across the distal ulna.
Because these results suggest that within reasonable ranges of ulnar variance loading across the distal ulna is independent of ulnar variance, the clinically observed incidence of ulnar impaction is more likely the result of increased wear on a thinner and less durable triangular fibrocartilage complex than due to increased distal ulna loading in ulnar positive variant wrists.
更准确地确定在特定腕部和前臂位置进行腕部运动和前臂运动时的正常腕关节力，并探究这些力与尺骨变异量之间是否存在关系。第二个目的是确定三角纤维软骨复合体关节盘厚度与通过尺骨远端传递的力的大小之间的关系。
将多轴测力传感器附着于9具新鲜尸体前臂的桡骨远端和尺骨远端。使用改良的腕关节模拟器使每个腕部进行腕部和前臂运动时，记录轴向桡侧和尺侧压缩力。在每次运动过程中，记录引起每次运动所需的肌腱力。测量尺骨变异和三角纤维软骨复合体关节盘厚度。
前臂旋前时，通过尺骨远端的轴向力和腕伸肌力量最大。未发现通过尺骨远端的力的大小与尺骨变异量之间存在关系。发现三角纤维软骨复合体厚度与尺骨变异之间存在强烈的负相关关系。
一般认为，尺骨变异为正的腕部在尺骨远端传递更大的负荷，这被认为使这些腕部易发生尺骨撞击。本研究结果似乎表明，无论尺骨变异如何，所有腕部在尺骨远端的负荷相似。相比之下，旋前相对增加了尺骨远端的负荷。
由于这些结果表明，在尺骨变异的合理范围内，尺骨远端的负荷与尺骨变异无关，临床上观察到的尺骨撞击发生率更可能是由于较薄且耐用性较差的三角纤维软骨复合体磨损增加所致，而非尺骨变异为正的腕部中尺骨远端负荷增加所致。
