Role of coracoacromial ligament and related structures in glenohumeral stability: a cadaveric study

This study sought to determine the role of the coracoacromial ligament and related arch structures in glenohumeral joint stabilization. Eight fresh-frozen cadaver specimens were tested at multiple angles of glenohumeral abduction and rotation for translations (in the direction of and perpendicular to a 50-N force) in intact, vented shoulders and after three interventions: coracoacromial veil release, coracoacromial ligament release, and anterior acromioplasty. After releasing the veil, an inferior force significantly increased inferior translation at lower angles of abduction with no additional increase after coracoacromial ligament section or acromioplasty. After ligament release or acromioplasty, a superior force increased superior translation at all angles. Few increases in anterior or posterior translations were observed. The coracoacromial veil interacts with the structures of the coracoacromial arch and glenohumeral capsule to limit inferior humeral translation. Likewise, the coracoacromial ligament and the acromian serve to limit superior translation. Attempts to preserve these structures may help improve surgical outcomes.