Erickson, Brandon J.

Background: There are many risk factors for shoulder and elbow injuries in professional baseball pitchers. The elbow carrying angle has not been studied as a potential risk factor. Purpose/Hypothesis: The aim of this study was to determine whether elbow carrying angle is a risk factor for shoulder or elbow injuries in professional baseball pitchers. We hypothesized that pitchers with a higher elbow carrying angle would be less likely to sustain an injury during the season than pitchers with a lower elbow carrying angle. Study Design: Cohort study; Level of evidence, 2. Methods: All professional pitchers for a single baseball club during the 2018 season had the carrying angle of both elbows measured at spring training by a single examiner. The pitchers were followed prospectively throughout the season. Shoulder and elbow injuries were recorded prospectively. Results: A total of 52 pitchers (21 [40%] Major League Baseball and 31 [60%] Minor League Baseball) were included. During the season, 23 (44%) pitchers became injured. The mean carrying angle in the throwing arm was 12.5° ± 4.2° versus 9.9° ± 2.8° in the nonthrowing arm ( P < .001). Comparing the injured and noninjured groups, there were no differences in level of play ( P = .870), throwing hand dominance ( P = .683), batting hand dominance ( P = .554), throwing-side carrying angle ( P = .373), nonthrowing-side carrying angle ( P = .773), or side-to-side difference in carrying angle ( P = .481). Conclusion: The elbow carrying angle was not associated with an injury risk during a single season in professional baseball pitchers.

Background: The medial ulnar collateral ligament (UCL) insertion of the elbow has been shown to extend distally beyond the sublime tubercle. The contribution to valgus stability of the distal aspect of the footprint is unknown. Purpose/Hypothesis: The purpose of this study was to determine the contribution of each part of the UCL footprint to the elbow valgus stability provided by the UCL. It was hypothesized that the distal two-thirds of the ulnar UCL footprint would not contribute significantly to valgus stability provided by the UCL. Study Design: Descriptive laboratory study. Methods: Fifteen cadaveric arms were dissected to the capsuloligamentous elbow structures and potted. A servohydraulic load frame was used to place 5 N·m of valgus stress on the intact elbow at 30°, 60°, 90°, and 120° of flexion. The UCL insertional footprint was measured and divided into thirds (proximal, middle, and distal). One-third of the UCL footprint was elevated off the bone (leaving the ligament in continuity), and the elbow was retested at the same degrees of flexion. This was repeated until the entire UCL footprint on the ulna was sectioned. Each elbow was randomized for how the UCL would be sectioned (sectioning the proximal, then middle, and then distal third or sectioning the distal, then middle, and then proximal third). Ulnohumeral joint gapping (millimeters) was recorded with a 3-dimensional motion capture system using physical and virtual markers. Two-group comparisons were made between each sectioned status versus the intact condition for each flexion angle. Results: When the UCL was sectioned from distal to proximal, none of the ligaments failed prior to complete sectioning. When the UCL was sectioned from proximal to distal, 3 of the 6 ligaments failed after sectioning of the proximal third, while 2 more failed after the proximal and middle thirds were sectioned. Of the specimens with the distal third of the ligament sectioned first, no significant differences were found between intact, distal third cut, and distal plus middle thirds cut at all flexion angles. Conclusion: The middle and distal thirds of the insertional footprint of the UCL on the ulna did not significantly contribute to gap resistance at 5 N·m of valgus load. The proximal third of the footprint is the primary resistor of valgus load. Clinical Relevance: This cadaveric biomechanical study demonstrated that the middle and distal thirds of the native UCL insertion onto the ulna did not significantly contribute to valgus resistance at the elbow. When a UCL reconstruction is performed, the proximal third of the UCL insertion may be the most clinically important portion of the ligament to reconstruct.

Objectives: In the setting of ulnar collateral ligament (UCL) injury, surgical reconstruction of the UCL is not always selected, as it leads to a prolonged recovery time and return to play rates between 67-95%. To date, there is limited data on outcomes following nonoperative treatment in this population. Orthobiologics, such as platelet-rich plasma (PRP), have recently been used as an adjunct therapy for standard nonoperative treatment including rest and physical therapy for UCL injuries. The objective of this study was to determine if the addition of PRP injections in professional baseball players with UCL injuries reduces recovery time, lowers the likelihood of surgery, and increases the return to play rate compared to traditional nonoperative treatment. Methods: The Health and Injury Tracking System (HITS) database was searched from 2011-2015 for Major and Minor league baseball players with Grade I, II or III UCL injuries. Standard demographic, injury, and return to play data was obtained for all players. MRI’s for 353 athletes were reviewed by a musculoskeletal radiologist and graded accordingly. Outcomes were compared between players who received PRP injections in addition to traditional nonoperative treatment (PRP group) and players who received traditional nonoperative treatment alone (No PRP group). Statistical analysis was performed using Student’s T-test and Chi-square for parametric data. Kaplan Meier’s analysis was used for estimating longevity of the treatment. Results: A total of 544 Major and Minor League Baseball players with UCL tears underwent an initial course of nonoperative treatment (active rest & rehabilitation) for their injury between 2011-2015. Of these, 133 underwent PRP injections plus rehab and 411 underwent rehab alone. There was a significantly higher proportion of Major League Baseball players in the PRP group compared to the No PRP group (25.6% vs 9.0%, P<0.001). There was no difference between the two cohorts in regard to the grade of UCL tear (Figure 1). The players in the PRP group had a significantly longer time before returning to a throwing program compared to the No PRP group (64 days vs 51 days, P<0.001). The mean time from injury date to PRP injection was 14.5 days, which may explain the difference in time to return to throwing. The return to play rate in a live game without surgery was significantly lower in the PRP group compared to the No PRP group (46% vs 57%, P=0.03). There was no difference in the proportion of athletes requiring UCL reconstruction (58% vs 51%) or the time to surgery (154 days vs 178 days) between the two groups. Kaplan Meier survivor analysis showed no difference between the PRP and No PRP groups with regard to longevity of the native UCL (Figure 2). Conclusion: Among Major and Minor League Baseball players who were treated nonoperatively for a UCL injury between 2011-2015, 24% underwent PRP injections prior to rehab. Compared to traditional nonoperative rehab alone program, players who received PRP injections experienced a significantly longer time before returning to throwing, which may be in part due to the delay between the injury date and PRP injection. PRP injections did not appear to have a significant effect on the likelihood of surgical intervention.