A Comparison of Glenohumeral Internal and External Range of Motion and Rotation Strength in Healthy and Individuals with Recurrent Anterior Instability

Background:  The glenohumeral joint becomes dislocated more than any other major joint because it maintains a wide range of motion and its stability is inherently weak. The most common complication following acute initial shoulder dislocation is recurrent dislocation or chronic instability. Imbalance of strength and range of motion in individuals with anterior dislocation can be a contributing factor in recurrent dislocation as well.  Methods:  This case-control study consisted of ۲۴ individuals with a mean age of ۲۴.۲۹±۴.۳۳ years, and a mean dislocation rate of ۵.۳۷±۳.۶۲ times. Isometric cuff strength was measured using a handheld dynamometer and for range of motion, the Leighton flexometer was used in internal and external rotational motions of both upper extremities. Independent t-test was used for data analysis. Results:  The internal and external range of motion of the injured glenohumeral joint was lower than the uninjured joint (P<۰.۰۰۱). Similarly, the internal and external rotation strength of the injured joint was lower than the uninjured joint (P<۰.۰۰۱).  Conclusions:  According to previous data, imbalance of strength and range of motion in individuals with anterior shoulder dislocation can be a contributing factor in long-term disability and increased recurrent dislocation and our finding confirm decreased range of motion and strength in our patients. Hence, proper exercise and rehabilitation plans need to be developed for those suffering from this complication.