Biomechanical effects of arthroscopic capsulorrhaphy in line with the fibers of the anterior band of the inferior glenohumeral ligament.

Abstract

There is no consensus as to the amount and direction of capsular plication necessary to correct anterior shoulder instability without overconstraining the joint. An arthroscopic capsulorrhaphy in line with the fibers of the inferior glenohumeral ligament (IGHL) in an anterior laxity model will restore glenohumeral kinematics to normal. Controlled laboratory study. Six cadaveric specimens were tested in both the scapular and coronal plane in 3 conditions: intact, anterior instability, and plicated. The anterior instability model was created by stretching the shoulder 20% beyond the physiological external rotational range of motion, and plication was achieved by performing a 10-mm arthroscopic plication in line with the fibers of the anterior band of the IGHL. Stretching significantly increased the rotational range of motion, while plication restored it back to that of the intact condition (P < .05). There were few significant changes in humeral head apex position across all 3 testing conditions. Plication significantly reduced anterior translation compared with the stretched condition (P < .05). Stretching and plication both significantly reduced contact area relative to the intact condition (P < .05). There were no significant differences between any of the 3 conditions for contact pressure and only few significant differences between the conditions for contact peak pressure. A 10-mm capsular plication in line with the fibers of the anterior band of the IGHL effectively reduces capsular laxity without overconstraining the joint. The fibers of the anterior band of the IGHL provide a useful arthroscopic anatomic landmark for the direction of anterior capsulorrhaphy.