Purpose or Case Report: We present a case of an 18YO male high school baseball player with acute onset posterior pain in his non-throwing left shoulder, the leading shoulder in his batting swing. Pain began on a missed attempt at hitting an outside pitch. The pain only occurred when he was batting and resulted in subsequent loss of batting power and accuracy. Patient was asymptomatic when he was not batting. Prior to the acute event, patient had low grade pain in this location during intermittent at bats. Physical exam showed 1-2+ left shoulder posterior instability and mildly asymmetric left less than right shoulder strength. He had negative Neer, Whipple, Speed’s, and Hawkin’s tests. MRI left shoulder showed posterior labral tear with paralabral cyst. Patient underwent laparoscopic posterior labral repair with placement of four anchoring sutures and Bankart reconstruction. He did well post-operatively, returning to preinjury strength and range of motion in four months and returning to play in 6 months.
Batter’s shoulder is a rare condition recently recognized in the orthopedic literature and has not been reported to our knowledge in the radiologic literature. Although the adolescent/young adult spectrum of shoulder injuries in the throwing arm have been well described, injury types and mechanisms involving the non-throwing arm are not commonly known. The mechanics of hitting places considerable stress on the leading shoulder. Biomechanics studies by Welch CM et al show that as the hitter slides forward, the force applied by the front foot equals 123% of body weight and the hip segment rotates to a maximum speed of 714 degrees/second. This is followed by maximum shoulder segment velocity of 937 degrees/second and maximum linear bat velocity of 31 m/second. During a missed pitch, these forces are magnified due to lack of a counterforce against the dynamic posterior pulling force on the lead shoulder. Athletes with labral tear of the leading shoulder during batting (Batter’s shoulder) have a better prognosis than throwing arm labral tear, with approximately 90% returning to previous level of play.
This exhibit will display biomechanics, pre-operative and post-operative MRIs, and intra-operative laparoscopic images of Batter’s Shoulder.
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