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Biceps Pathology and Its Relation to Humeral Torsion in Professional Baseball Pitchers

      Introduction

      Biceps pathology is common in the dominant arm of professional pitchers. Repetitive throwing causes increased mechanical stress that has been associated with altered bony morphology. There have been no clinical studies assessing the characteristics of the biceps tendon in relation to humeral torsion in professional baseball pitchers. This study was used to examine humeral torsion in those pitchers presenting with abnormal versus normal biceps tendons.

      Methods

      A bilateral ultrasound examination was performed on 30 pitchers from one professional baseball club. The biceps was characterized as normal if the biceps appearance was hyperechoic and uniform thickness. It was abnormal if the biceps was subluxed or dislocated from the groove, the tendon was thickening with abnormal echo texture, the tendon presented with a halo sign or demonstrating fluid distension around the sheath. The reliability for humeral torsion measures was acceptable with ICC’s =.99 and SEM=1.3. The inter rater reliability for characterization of the biceps tendon was Kappa =.89. A one-way ANOVA was performed to determine the difference in humeral torsion between those with abnormal versus normal biceps tendons.

      Results

      Eighty percent of the dominant biceps tendons were characterized as abnormal. The dominant shoulders with abnormal biceps tendons had a significantly more antetorsion on the dominant side than those presenting with normal biceps. (15.1±9.7 vs. 5.4±11.1;P= 0. 05).

      Conclusion

      Eighty percent of the dominant shoulders in professional baseball pitchers had abnormal biceps. Professional pitchers with abnormal biceps also displayed less humeral retrotorsion compared to pitchers with normal biceps. Recently we have shown that pitchers with less humeral retrotorsion are more at risk for shoulder pain. The lack of humeral retrotorsion and associated pathological imaging of the biceps may represent subclinical findings in these pitchers. Our results suggest future studies should examine the influence of humeral torsion and biceps abnormalities in professional pitchers.