Hospital for Special Surgery, New York, New York, USA.
Am J Sports Med. 2010 Dec;38(12):2535-41. doi: 10.1177/0363546510376231. Epub 2010 Sep 9.
Previous studies have documented increased posteromedial contact forces with the elbow at lower flexion angles associated with valgus extension overload; however, the authors believe that posteromedial elbow impingement in association with valgus laxity is a complex pathological process that may occur throughout the entire throwing motion in the form of ulnohumeral chondral and ligamentous overload.
Valgus laxity with the elbow at 90° of flexion may lead to chondromalacia secondary to a subtle shift in the contact point between the tip of the olecranon and the distal humeral trochlea.
Controlled laboratory study.
Six fresh human cadaveric elbows were dissected and subjected to a static valgus load. Pressure-sensitive Fuji film measured the contact pressure, contact area, and shift in contact area across the posteromedial elbow before and after sectioning the anterior bundle of the ulnar collateral ligament.
The contact pressure between the tip of the olecranon process and the medial crista of the posterior humeral trochlea significantly increased, from an average of 0.27 ± 0.06 kg/cm² to 0.40 ± 0.08 kg/cm². The contact area also significantly decreased, from an average of 30.34 ± 9.17 mm² to 24.59 ± 6.44 mm², and shifted medially on the medial humeral crista, which corresponds to the position of the posteromedial chondral lesions that was observed in throwing athletes in the authors' clinical practice.
While simulating the early acceleration phase of the throwing motion with the elbow in 90° of flexion, the results illustrate that abnormal contact may occur as a result of valgus laxity through increased contact pressures across the posteromedial elbow between the medial tip of the olecranon and medial crista of the humeral trochlea. In addition, congruency of the ulnohumeral joint changed, as there was a statistically significant medial shift of the olecranon on the posterior humeral trochlea with the elbow at 90° of flexion after sectioning the anterior bundle of the ulnar collateral ligament.
In the throwing athlete who continues the repetitive, throwing motion despite valgus laxity from ulnar collateral ligament insufficiency, the authors believe that these results provide a plausible mechanism for injury throughout the entire throwing motion secondary to ulnohumeral chondral and ligamentous overload. As throwing athletes may produce a tremendous amount of force and subsequent chondromalacia within the posteromedial aspect of the elbow, the findings of this study illustrate the importance of prompt clinical recognition of ulnar collateral ligament insufficiency.
先前的研究已经证明，在较低的屈曲角度下，肘后内侧接触力会随着外翻延伸过载而增加；然而，作者认为，与外翻松弛相关的肘后内侧撞击是一个复杂的病理过程，可能会在整个投掷运动中以尺肱软骨和韧带过载的形式发生。
在屈曲 90°的肘部，外翻松弛可能会导致软骨下骨软化，这是由于鹰嘴尖端和肱骨滑车远端滑车后内侧接触点的微妙移位所致。
对照实验室研究。
对 6 个新鲜的人体肘部标本进行解剖，并施加静态外翻负荷。富士胶片压力感应片测量肘后内侧的接触压力、接触面积和接触面积的移位，在切断尺侧副韧带前束之前和之后进行。
鹰嘴尖端和肱骨滑车后内侧嵴之间的接触压力显著增加，从平均 0.27±0.06kg/cm²增加到 0.40±0.08kg/cm²。接触面积也显著减小，从平均 30.34±9.17mm²减小到 24.59±6.44mm²，并且在尺骨内侧嵴上向内侧移位，这与作者临床实践中投掷运动员的后内侧软骨病变的位置相对应。
在模拟投掷运动早期加速阶段时，结果表明，由于外翻松弛，肘在 90°屈曲时，可能会导致异常接触，导致尺骨鹰嘴内侧尖端和肱骨滑车后内侧嵴之间的肘后内侧出现较高的接触压力。此外，尺肱关节的一致性发生了变化，在前束切断后，在肘屈曲 90°时，鹰嘴在肱骨滑车后内侧嵴上出现统计学上显著的内侧移位。
在患有尺侧副韧带不足导致外翻松弛但仍继续进行重复性投掷运动的投掷运动员中，作者认为，这些结果为整个投掷运动中由于尺肱软骨和韧带过载导致的损伤提供了一个合理的机制。由于投掷运动员可能在肘后内侧产生大量的力和随后的软骨下骨软化，因此本研究的结果说明了及时临床识别尺侧副韧带不足的重要性。
