Throwing acquired anterior rotator interval pathology

Abstract

Hidden lesions of the rotator interval capsule are a well-defined pathologic entity in the throwing shoulder with characteristic imaging and exam findings. The biceps pulley, part of the interval capsule, is comprised of the SGHL, CHL, and supraspinatus tendon. Stretching of the CHL can occur with repeated external rotation stress. SGHL failure may result from repetitive cross arm follow-through during pitching. Stretching of the CHL and or SGHL may result in biceps instability and anterior shoulder pain. Interval lesions may occur in combination with any lesion of the labrum. An arthroscopic interval placation restores normative interval dimensions and eradicates biceps pulley instability. Failure to treat interval laxity in the setting of shoulder instability, especially in the throwing athlete, will result in suboptimal surgical outcomes. The high rate of failure in labral surgery may be explained by omission of addressing the interval lesion.