Background:Injuries to the medial ulnar collateral ligament (UCL) are common among baseball pitchers due to repetitive stress on the soft tissue stabilizers of the elbow during pitching. Dynamic stress ultrasound (SUS) can be used to evaluate the UCL and ulnohumeral joint to identify anatomic risk factors of those who will require UCL reconstruction (UCLR).Purpose:To determine whether any adaptive or morphological changes detectable on SUS can predict injury to the UCL in professional baseball pitchers.Study Design:Cohort study; Level of evidence, 3.Methods:A total of 203 professional baseball pitchers who underwent SUS at preseason training sessions over the course of 18 years were categorized into 1 of 2 groups: those without a history of shoulder, arm, elbow, or forearm surgery or injuries (healthy cohort; n = 184) and those who underwent UCLR the same season as SUS (UCLR cohort; n = 19). Ligament thickness, joint spacing, and laxity were compared. An additional matched cohort analysis was conducted using 10 players from each group to detect differences in the progression of UCL and ulnohumeral joint measures in the year before injury.Results:The UCLR cohort, when compared with the healthy cohort, had higher relative (ie, nondominant-side measurements subtracted from dominant-side measurements) resting ulnohumeral joint space (median, 0.50 vs 0.20 mm, respectively; P = .006) and higher rates of hypoechoic foci (57.9% vs 30.4%, respectively; P = .030). Players of both groups had similar dominant UCL thickness ( P = .161), ulnohumeral joint space at rest ( P = .321), space under stress ( P = .498), and laxity ( P = .796). Groups did not differ in terms of relative UCL thickness, ulnohumeral joint space under stress, or relative laxity. In the year before UCL injury, the UCLR cohort, compared with the matched healthy cohort, had a greater increase in mean dominant UCL thickness (0.94 vs –0.60 mm, respectively; P = .038) and a greater increase in relative median UCL thickness (1.35 vs –0.35 mm, respectively; P = .045). Players in the healthy cohort were statistically older than those in the UCLR cohort (23 vs 22 years, respectively; P = .004). No differences in ulnohumeral stress spacing or laxity were detected.Conclusion:SUS of players who underwent UCLR demonstrated a progressive increase in UCL thickness over 1 year, higher rates of hypoechoic foci, and increased ulnohumeral rest space compared with SUS of uninjured players.

中文翻译：

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应力超声在识别肘部尺侧副韧带撕裂危险因素中的应用：对 203 名职业棒球运动员的纵向研究

背景：内侧尺侧副韧带（UCL）损伤在棒球投手中很常见，因为投球过程中肘部软组织稳定器受到重复性压力。动态应力超声 (SUS) 可用于评估 UCL 和尺肱关节，以确定需要 UCL 重建 (UCLR) 的患者的解剖学危险因素。 目的：确定 SUS 上可检测到的任何适应性或形态学变化是否可以预测肱骨损伤伦敦大学学院职业棒球投手研究设计：队列研究；证据级别，3.方法：共有 203 名职业棒球投手在 18 年的季前训练中接受了 SUS，被分为 2 组中的一组：没有肩部、手臂、肘部或前臂手术史的人或受伤的人（健康队列；n = 184）以及与 SUS 同一赛季接受 UCLR 的人（UCLR 队列；n = 19）。比较韧带厚度、关节间距和松弛度。使用每组 10 名球员进行了额外的匹配队列分析，以检测受伤前一年 UCL 和肱尺关节测量进展的差异。 结果：与健康队列相比，UCLR 队列具有更高的相对（即，从主导侧测量值中减去非主导侧测量值）静息肱骨关节间隙（中位分别为 0.50 毫米与 0.20 毫米；P = .006）和较高的低回声灶发生率（分别为 57.9% 与 30.4%；P = .030） 。两组球员的主要 UCL 厚度 (P = .161)、静止时肱骨关节间隙 (P = .321)、压力下间隙 (P = .498) 和松弛度 (P = .796) 相似。各组在相对 UCL 厚度、压力下肱骨关节间隙或相对松弛方面没有差异。在 UCL 损伤前一年，与匹配的健康队列相比，UCLR 队列的平均显性 UCL 厚度增加更大（分别为 0.94 毫米和 –0.60 毫米；P = .038），并且相对中位 UCL 厚度增加更大。 （分别为 1.35 与 –0.35 毫米；P = .045）。健康队列中的玩家在统计上比 UCLR 队列中的玩家年龄更大（分别为 23 岁和 22 岁；P = .004）。未检测到肱骨应力间距或松弛度存在差异。 结论：与未受伤运动员的 SUS 相比，接受 UCLR 的 SUS 运动员的 UCL 厚度在 1 年内逐渐增加，低回声灶发生率更高，并且肱骨休息空间增大。