O1252 EXPERIMENTAL STUDY OF THE CONSEQUENCES OF LABRAL AND CAPSULOLABRAL LESIONS ON SHOULDER STABILITY

Abstract

Aim: To determine whether isolated lesions of the glenoid labrum or capsulolabral lesios influence anterior and inferior shoulder stability in a cadaver model that leaves all other glenohumeral structures, including the capsule, intact. Methods: Sequential arthroscopic resection of the labrum was performed with a motorized shaver in seventeen fresh cadaver shoulders. A capsulolabral dehiscence was created arthroscopically in another eleven fresh cadaver shoulders. The capsulolabral complex was divided into five zones: from superior to posterior. Inferior and anterior stability were tested before and after each cutting step. Results: The hyper-abduction test showed progressive increase in abduction with each step, with a maximum of 120° reached after removal of the labrum in all four zones or after detachment of all zones. Resection of the superior to inferior labrum maximally resulted in subluxation, but not in dislocation of the shoulder. Capsulolabral dehiscence of all but the posterior zones resulted in a locked (6/11) or a metastable (4/11) dislocation. In the other specimens the posterior zone needed to be detached as well for a metastable dislocation. Conclusion: Purely labral lesions and limited capsulolabral detachments do not seem to be sufficient to allow the humeral head to dislocate. Labral tears can therefore be debrided without consequences for shoulder stability. In the present study, a capsulolabral detachment in the antero-inferior zone (the typical Bankart lesion) does not allow the humeral head to dislocate. This leads us to suggest that associated lesions must exist in chronic instability.