Posterior Capsular Tightness in Throwers with Internal Impingement
Authors: Joseph B Myers, PhD Pittsburgh PA
References: AAOS 2005
Throwers with internal impingement exhibited significantly increased posterior capsular tightness and greater internal rotation deficits compared to control throwers.
Posterior capsular tightness (PCT) and glenohumeral internal rotation deficit (GIRD) that exceeds the accompanying external rotation gain (ERG) are suggested contributors to throwing related shoulder injuries, including internal impingement. Yet, these contributors have not been identified in throwers with internal impingement. The purpose was to assess GIRD, ERG, and PCT in throwers diagnosed with internal impingement.
Eleven throwing athletes diagnosed with internal impingement using both clinical examination and a gadolinium enhanced MRI, were demographically matched with eleven control throwers with no history of upper extremity injury. Passive glenohumeral internal and external rotation were measured bilaterally with standard goniometry at a position of 90 degrees of humeral abduction. Bilateral differences in glenohumeral range of motion were used to calculate GIRD and ERG. PCT was quantified as the bilateral difference in shoulder horizontal adduction present with the scapula retracted and shoulder positioned in 90Â° of elevation. Comparisons were made between groups with dependent t-tests (p < .05).
The throwing athletes with internal impingement demonstrated significantly greater GIRD (p equals 0.03) and PCT (p equals.01) compared to the control subjects. No significant differences were observed in ERG between groups.
Throwers with internal impingement exhibited significantly increased PCT and GIRD without the necessary accompaniment of ERG. These findings indicate the presence of posteroinferior capsular contracture that may contribute to impingement of the posterior rotator cuff tendon(s) and labrum by shifting the glenohumeral contact point posterosuperiorly during the abduction/external rotation position associated with both throwing and internal impingement.