EFFECT OF HUMERAL HEAD DEFECT SIZE ON GLENOHUMERAL STABILITY: A CADAVERIC STUDY OF SIMULATED HILL-SACHS DEFECTS

BackgroundHill-Sachs lesions are often present with recurrent shoulder instability and may be a cause of failed Bankart repair.HypothesisGlenohumeral joint stability decreases with increasingly larger humeral head defects.Study DesignDescriptive laboratory study.MethodsHumeral head defects, 1/8, 3/8, 5/8, and 7/8 of the humeral head radius, were created in 8 human cadaveric shoulders, simulating Hill-Sachs defects. Testing positions included 45° and 90° of abduction and 40° of internal rotation, neutral, and 40° of external rotation. Testing occurred at each defect size sequentially from smallest to largest for all abduction and rotation combinations. The humeral head was translated at 0.5 mm/s 45° anteroinferiorly to the horizontal glenoid axis until dislocation. Distance to dislocation, defined as humeral head translation until it began to subluxate, was the primary outcome measure.ResultsSignificant factors by ANOVA were rotation (P < .001) and defect size (P < .001). There was no difference for the 2 ...