Changes in the Structural Properties of the UCL in Collegiate Baseball Pitchers

Perhaps the most serious injury for a baseball pitcher is a full tear of the ulnar collateral ligament (UCL) in their throwing arm. Full tears of the UCL require surgical reconstruction if the athlete hopes to return to throwing at the same level. The UCL , which is the primary stabilizer of the medial elbow , is exposed to high valgus stresses during the baseball pitching motion. Very few studies have performed pre- and post-season ultrasound imaging to measure the properties of the UCL , and none have performed mid-season imaging at regular intervals in order to track changes in the UCL. There is a need for better understanding of the changes which take place in the UCL of baseball pitchers prior to suffering a significant injury to the UCL in their throwing arm in order to help decrease the alarming rate of UCL tears in baseball pitchers. The primary purpose of this study was to examine changes in the structural properties of the UCL and medial elbow in NCAA Division I collegiate baseball pitchers over the course of a season. The secondary purpose of this research was to determine if relationships exist between recent throwing load , upper body resistance training , and perceived medial elbow stiffness with any observed changes in the structural properties of the UCL and medial elbow. To evaluate these purposes , we performed biweekly ultrasound imaging on 12 healthy collegiate baseball pitchers throughout the course of a collegiate baseball season. Four structural properties of the UCL were measured for each imaging session , including the length and thickness of the ligament , UCL space , and the ulnohumeral gap. Participants completed questionnaires reporting their pitching and resistance training workload , as well as perceived elbow stiffness variables in order to evaluate any potential correlations between changes in the UCL and these self-reported metrics. The results of the imaging sessions displayed significant bilateral differences in UCL properties at the pre- and post-season timepoints , and significant changes in the properties of the UCL in the participants' throwing arms compared to the pre-season imaging session. Our results did not show any significant changes between biweekly imaging sessions for any of the structural properties of the UCL in the throwing arms of our participants. The results of this study demonstrate the continued need for a new method of measuring the health of a baseball pitcher's throwing arm , specifically the UCL , in order to determine when throughout a season , and the factors that lead to , a pitcher being at an elevated risk of tearing the UCL. Such information would be helpful to the coaching , training , and medical staffs involved with high level baseball , who attempt to aid pitchers in remaining healthy and increasing their pitching performance