Biomechanical Effects of Arthroscopic Capsulorrhaphy in Line With the Fibers of the Anterior Band of the Inferior Glenohumeral Ligament

Abstract

Background: There is no consensus as to the amount and direction of capsular plication necessary to correct anterior shoulder instability without overconstraining the joint.

Hypothesis: 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.

Study Design: Controlled laboratory study.

Methods: 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.

Results: 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.

Conclusion: 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.

Clinical Relevance: The fibers of the anterior band of the IGHL provide a useful arthroscopic anatomic landmark for the direction of anterior capsulorrhaphy.