Quantification of anterior translation of the humeral head in the throwingshoulder - Manual assessment versus stress radiography

Clinical evaluation of humeral head translation relies mainly on manual tes ts to measure laxity in the human shoulder. The purposes of this study were to determine whether side-to-side differences exist in anterior humeral he ad translation in professional baseball pitchers, to compare manual laxity testing with stress radiography for quantifying humeral head translation, a nd to test intrarater reliability of the manual humeral head translation an d stress radiography tests. Twenty professional baseball pitchers underwent bilateral manual anterior humeral head translation and stress radiographic tests. Stress radiography was performed by imparting a 15-daN anterior loa d to the shoulder in 90 degrees of abduction with both neutral and 60 degre es of external rotation and recording the glenohumeral joint translation at rest and under stress in each position. Eight subjects were retested to as sess the reliability of these methods. Results showed no significant differ ence between the dominant and nondominant extremity in the amount of anteri or humeral head translation measured manually and with stress radiography, nor significant correlation between anterior humoral head translation measu red manually and by stress radiography. Test-retest reliability was moderat e-to-poor for the manual humoral head translation test and moderate for str ess radiography.