Beuerlein Murray J, Reid Jeffrey T, Schemitsch Emil H, McKee Michael D
Upper Extremity Reconstructive Service, St. Michael's Hospital and the University of Toronto, 55 Queen Street East, Suite 800, Toronto, ON M5C 1R6, Canada.
J Bone Joint Surg Am. 2004 Oct;86(10):2235-42. doi: 10.2106/00004623-200410000-00015.
Recent reports have implicated cubitus varus deformity as a risk factor for the development of late posterolateral rotatory instability of the elbow. The purpose of this study was to determine the biomechanical relationship between cubitus varus and strain in the lateral ulnar collateral ligament and subluxation of the ulnohumeral joint as it relates to posterolateral rotatory instability.
Eleven fresh-frozen cadaveric elbow joints were mounted in an apparatus that allowed active elbow motion. Supracondylar osteotomies were performed to create cubitus varus deformities of 0 degrees to 30 degrees in 5 degrees increments. Each elbow was loaded with a supination moment of 1.2 Nm and a resistive triceps extension force. Strain in the lateral ulnar collateral ligament and widening of the ulnohumeral joint were measured at each position of varus, and the resulting strain and joint-widening values were averaged.
Strain in the lateral ulnar collateral ligament was found to increase as the cubitus varus deformity increased. Likewise, the ulnohumeral joint space was seen to progressively widen with increasing cubitus varus. Strain was significantly increased at 30 degrees of varus deformity (p = 0.03), and widening of the ulnohumeral joint space was significantly increased at 25 degrees of varus deformity (p = 0.004). When differences in the size of the cadaveric specimens were accounted for in an analysis of covariance, ligament strain was significantly increased at 25 degrees of varus (p = 0.005) and widening of the ulnohumeral joint space, at 20 degrees (p = 0.01).
Cubitus varus deformity of the elbow increases strain in the lateral ulnar collateral ligament, with a corresponding increase in ulnohumeral joint-opening consistent with the posterolateral rotatory instability of the elbow seen clinically.
近期报告表明肘内翻畸形是导致肘关节晚期后外侧旋转不稳定的一个风险因素。本研究的目的是确定肘内翻与尺侧副韧带应变以及尺肱关节半脱位之间的生物力学关系，因为这与后外侧旋转不稳定相关。
将11个新鲜冷冻的尸体肘关节安装在一个允许肘关节进行主动活动的装置上。进行髁上截骨术，以5度的增量创建0度至30度的肘内翻畸形。每个肘关节施加1.2 Nm的旋后力矩和抗阻肱三头肌伸展力。在每个内翻位置测量尺侧副韧带的应变和尺肱关节的增宽，并将所得的应变和关节增宽值进行平均。
发现随着肘内翻畸形增加，尺侧副韧带的应变也增加。同样，随着肘内翻增加，尺肱关节间隙逐渐增宽。在30度内翻畸形时应变显著增加（p = 0.03），在25度内翻畸形时尺肱关节间隙增宽显著增加（p = 0.004）。在协方差分析中考虑尸体标本大小差异时，在25度内翻时韧带应变显著增加（p = 0.005），在20度时尺肱关节间隙增宽显著增加（p = 0.01）。
肘关节的肘内翻畸形会增加尺侧副韧带的应变，同时尺肱关节开口相应增加，这与临床上所见的肘关节后外侧旋转不稳定一致。
