Anterior glenohumeral instability

Abstract

The understanding of and approach to anterior shoulder instability has changed and improved dramatically in recent years. It is now accepted that a shoulder can subluxate as well as dislocate and that chronic instability may or may not be caused by an initial traumatic event. An anteriorly unstable shoulder also can be unstable inferiorly and/or posteriorly (multi-directional instability). The author's diagnostic acumen has increased with the addition of glenohumeral axillary arthrotomography, glenohumeral CT arthrography, glenohumeral arthroscopy, and other studies. Surgical treatment has moved away from "repair of choice" to an "anatomic reconstruction." The current preferred treatment is to identify and repair only the pathology while preserving normal anatomy, hoping to restore shoulder stability, while preserving normal mobility and strength. Areas of controversy exist. 1) How long should acute dislocations be immobilized, if at all, and is physiotherapy helpful in preventing chronic instability? 2) How long should the surgically repaired shoulder be immobilized, if at all? 3) Is there a place for therapeutic arthroscopy in this area? Also controversial is the concept of "functional instability" or shoulder internal derangement. These patients are felt to have shoulder slipping and catching due to the intermittent interposition of a fragment of tissue (a torn labrum, a loose body, etc) between the articulating surfaces. Arthroscopic debridement of the pathology would be ideally suited for such a clinical entity. Undoubtedly, improvements and controversy will continue until orthopedists are able to accurately diagnose and correct shoulder instability, while preserving range of motion and strength at minimal inconvenience to the patient.