Gupta Nakul, Taylor Ross E, Lambert Bradley, Dong David, Phillips Paul, Jack Robert A, Goble Haley M, Labis John S, Trakhtenbroit Michael A, McCulloch Patrick C
Department of Radiology, Houston Methodist Hospital, Houston, TX, USA.
Department of Orthopedics and Sports Medicine, Houston Methodist Hospital, Houston, TX, USA.
JSES Int. 2023 Apr 11;7(4):703-708. doi: 10.1016/j.jseint.2023.03.014. eCollection 2023 Jul.
The ulnar collateral ligament (UCL) is a commonly injured elbow stabilizer during throwing. Shear wave elastography (SWE) is a technique that may reveal structural changes in the UCL that are indicative of ligament health and injury risk. The purpose of this study was to assess preseason and inseason shear wave velocity (SWV) in the UCL of collegiate pitchers and to asses repeatability of this measurement technique in healthy volunteers.
Seventeen collegiate baseball pitchers and 11 sex-matched volunteers were recruited. Two-dimensional SWE of the UCL was performed by a single radiologist. In pitchers, SWV was measured at the proximal, midsubstance, and distal UCL for dominant and nondominant elbows preseason, midseason, and postseason, and Kerlan-Jobe Orthopaedic Clinic (KJOC) Shoulder and Elbow questionnaire scores were recorded. In volunteers, SWV was measured at UCL midsubstance in dominant elbows at 3 separate occasions over 1 week. An independent samples -test was used to compare preseason midsubstance measures between pitchers and the healthy volunteers. A mixed-model analysis of covariance (covaried on preseason measures) was used to compare SWV measures at the preseason, midseason, and postseason time points. A similar generalized linear model for nonparametric data was used to compare KJOC scores. Type-I error was set at < .05.
Mean preseason midsubstance dominant arm UCL SWV did not significantly differ between the pitchers (5.40 ± 1.65 m/s) compared to the healthy volunteers (4.35 ± 1.45 m/s). For inseason measures among the pitchers, a decrease in midsubstance (-1.17 ± 0.99 m/s, = .021) and proximal (-1.55 ± 0.91 m/s, = .001) SWV was observed at midseason compared to preseason. The proximal measure was also observed to be significantly lower than the nondominant arm (-1.97 ± 0.95 m/s, < .001). Proximal SWV remained reduced relative to the preseason and the postseason mark (-1.13 ± 0.91 m/s, = .015). KJOC scores decreased at midseason compared to preseason ( = .003) but then increased to a similar preseason value at the postseason measurement (preseason = 92 ± 3, midseason = 87 ± 3, postseason = 91 ± 3). The repeatability coefficient of SWE in the volunteer cohort was 1.98 m/s.
Decreased SWV in the proximal and midsubstance of the dominant arm UCL at midseason suggests structural changes indicative of increasing laxity or 'softening' of the UCL. Associated decline in KJOC scores suggests that these changes are associated with functional decline. Future studies with more frequent sampling would be invaluable to further explore this observation and its significance for predicting and managing UCL injury risk.
尺侧副韧带（UCL）是投掷过程中肘部常见的损伤稳定结构。剪切波弹性成像（SWE）是一种可揭示UCL结构变化的技术，这些变化可指示韧带健康状况和损伤风险。本研究的目的是评估大学棒球投手赛季前和赛季中UCL的剪切波速度（SWV），并评估该测量技术在健康志愿者中的可重复性。
招募了17名大学棒球投手和11名性别匹配的志愿者。由一名放射科医生对UCL进行二维SWE检查。对于投手，在赛季前、赛季中和赛季后测量优势侧和非优势侧肘部UCL近端、中部和远端的SWV，并记录克尔兰 - 乔布骨科诊所（KJOC）肩部和肘部问卷评分。对于志愿者，在1周内分3次测量优势侧肘部UCL中部的SWV。采用独立样本t检验比较投手和健康志愿者之间赛季前中部的测量值。采用协方差混合模型分析（以赛季前测量值为协变量）比较赛季前、赛季中和赛季后时间点的SWV测量值。采用类似的非参数数据广义线性模型比较KJOC评分。设定I型错误率α<0.05。
与健康志愿者（4.35±1.45 m/s）相比，投手优势侧手臂UCL赛季前中部的平均SWV差异无统计学意义（5.40±1.65 m/s）。对于投手中的赛季中测量，与赛季前相比，中部（-1.17±0.99 m/s，P = 0.021）和近端（-1.55±0.91 m/s，P = 0.001）的SWV降低。还观察到近端测量值显著低于非优势侧手臂（-1.97±0.95 m/s，P<0.001）。近端SWV相对于赛季前和赛季后标记仍降低（-1.13±0.91 m/s，P = 0.015）。与赛季前相比，KJOC评分在赛季中降低（P = 0.003），但在赛季后测量时增加到类似的赛季前值（赛季前=92±3，赛季中=87±3，赛季后=91±3）。志愿者队列中SWE的重复性系数为1.98 m/s。
赛季中优势侧手臂UCL近端和中部的SWV降低表明结构变化，提示UCL松弛增加或“软化”。KJOC评分的相关下降表明这些变化与功能下降有关。未来更频繁采样的研究对于进一步探索这一观察结果及其对预测和管理UCL损伤风险的意义将非常有价值。
