Sonography Of The Supraspinatus Tendon In Baseball Players That Play Different Positions, An Observational Study

PURPOSE:Functional subacromial impingement syndrome (SIS) is reportedly common in overhead athletes under 35 years of age. It has been suggested that repetitive throwing may lead to increased inflammation and tendinopathy of the tissues in the subacromial space (SAS), particularly the supraspinatus tendon (SST). Chronic shoulder pain in overhead athletes may also be the result of sport specific adaptations driven by niche functional demands. Sonography is a reliable imaging modality for viewing the SAS and the SST and is accessible. This study investigated the difference in SAS, SST thickness, and subacromial occupancy ratio (SST thickness/SAS) between pitchers and nonpitchers on a collegiate baseball team.v METHODS:Sonography was used to evaluate SST thickness and SAS. One measurement was performed in the modified-Crass position to obtain long-axis images of the SST. SAS was measured in a neutral arm position from the anterior lateral tip of the acromion to the cortical surface of the humeral head directly inferior to the lateral tip of the acromion. Occupancy ratio was calculated by dividing SST thickness by SAS. MANOVA analysis was utilized to analyze the data. RESULTS: 44 male collegiate baseball players’ dominant shoulders (23 pitchers and 21 nonpitchers) were measured. Mean SAS for pitchers was 1.228 cm (SE .031) and for nonpitchers was 1.227 (SE .032). Mean SST thickness for pitchers was .714 (SE .022) and for nonpitchers was .677 (SE 0.23). Mean occupancy ratio for pitchers was 0.587 (SE .019) and for nonpitchers was .556 (SE .020). There were no statistically significant differences between positions for all variables (SAS (F = .001, p = .979), SST (F = 1.305, p = .260), occupancy ratio (F = 1.189, p = .282). CONCLUSIONS:In measurements obtained via sonography prior to the beginning of the season, there was no significant difference in the SAS, SST, or occupancy ratio between pitchers and nonpitchers on a collegiate baseball team. In the future, measurements will be repeated on the same subjects in order to assess the changes in SAS, SST and occupancy ration that occurred within groups from preseason and postseason assessments, as well as the difference in changes that occurred between groups in SAS, SST and occupancy ration from preseason and postseason assessment.