Thursday, May 8, 2014

The coracoacromial ligament. Why it needs to be preserved.

The coracoacromial (CA) ligament is one of the most important structures of the shoulder. Along with the rotator cuff it restrains the humeral head and prevents anterosuperior escape of the shoulder. Often times orthopaedic surgeons decide to sacrifice the ligament as part of the acromioplasty or Mumford procedure. Dividing the ligament during arthroscopy can have negative effects in the young patient population because the ligament contains mechanoreceptors which are important for the proprioception of the shoulder. Please see picture below

The negative effects of a torn CA ligament are depicted below. In the older patient population the rotator cuff progressively degenerates and in the absence of a CA ligament the humeral head migrates superiorly affecting the ability of the patients to raise their arm.
When the CA ligament is intact it restrains superior migration of the humeral head

When the CA ligament is divided or absent it does not restrain superior migration of the humeral head and a failed rotator cuff can lead to anterosuperior escape of the humerus during forward elevation of the shoulder