Thank you. This work was completed last year and I was a fellow at Curl and Jobe. We have no relevant disclosures for the talk. The relationship between GERD and throwing elbow injury remains debated. One possible reason is that prior studies have not accounted for the bony adaptations of the throwing humerus. Humeral retrotorsion, or the external twisting around the long axis of the bone, is now well documented osteas change in baseball players throwing arms. This intuitively rotates the shoulder arc of motion externally, contributing to non-pathologic GERD. So without knowing an individual's humeral torsion, limited side-to-side comparisons in range of motion can be made. Humeral retrotorsion has been documented in athletes as young as 11, with debated downstream effects on the elbow as well. The purpose of our study was to compare standard range of motion, humeral torsion, and humeral torsion corrected range of motion between healthy adolescent pitchers who are currently pitching in the community without complaints and pitchers presenting the clinic with a complaint of elbow pain related to throwing. Anyone with a surgical history in the throwing arm or known bony lesion of the humerus were excluded. We hypothesized that all pitchers would show gain in external rotation and loss of internal rotation, but that injured pitchers would show a loss only in corrected external rotation. Total humeral motion was measured using a bubble goniometer with the scapulothoracic joint manually stabilized. For injured subjects, measurements were taken either in clinic or in the OR if the procedure was indicated by the treating physician. A pilot study was completed to ensure no effect of anesthesia on measurements. Humeral torsion was measured using an ultrasound and bubble goniometer, as previously described by Ito and then validated in baseball players by Whiteley. Total arc of motion and corrected range of motion were calculated with simple arithmetic and then compared between and across groups with parametric tests for continuous variables. These are results starting off for healthy pitchers only. This group displayed a symmetric external rotation gain and internal rotation loss of roughly 14 degrees. The difference in humeral torsion between sides was also 14 degrees, so after correcting for this, no difference in range of motion remained. Although the numbers are different as we'll soon see, the same principle of external rotation gain and internal rotation loss corrected by torsion occurred in the injured population as well. So now I'm moving into a comparison across the groups. Injured pitchers showed 10 degrees less standard external rotation in the throwing shoulder without a difference in internal rotation. Although not significant, a trend towards decreased total arc of motion was also seen. No difference in humeral torsion was found between groups. And the difference between corrected external rotation after correcting for torsion remained. Interestingly, when comparing the non-dominant arms of the injured population to the healthy population, the injured also displayed decreased baseline standard external rotation as well. This was not statistically significant after correction for torsion. Based on this last finding, we then calculated Pearson's coefficient between humeral torsion and range of motion in the dominant arms in both directions and found a moderate or R greater than .5 correlation in both directions for the healthy group. But no correlation was found between these values in the injured group. This study is now without limitations. Our population is small and isolated to a specific geographic area. Healthy pitchers were also seen only once, so it's unknown if they sustained injury immediately after data collection. And other risk factors for elbow injury were also not accounted for. However, I do think we can make some important conclusions. First, torsion was not associated with injury in our study, which does go against some other previous reports. Second, torsion does contribute to motion change in healthy pitchers, but clearly another factor is at play in the injured group in our study. Lastly, decreased external rotation regardless of humeral torsion was associated with injury in adolescent pitchers in this study. Clinically, this last point I think is the most important. You know, if a patient comes into the office, I think most people are doing posterior shoulder stretches with sleeper stretches, and that's kind of been the dogma in pitching athletes for a long time now. And our study kind of suggests that external rotation stretches is just as important, if not even more important. So I think it's something that we need to look at more moving forward to see how much external rotation needs to be a focus of in-season maintenance and recovery following shoulder injuries to help them get back into that late cocking position. Thank you.

GERD

throwing elbow injuries

humeral retrotorsion

range of motion

shoulder injuries