Patterns of motion loss in subjects with idiopathic loss of shoulder range of motion

Background. Subjects with idiopathic loss of shoulder motion have difficulty sleeping, performing overhead activities, and completing activities of daily living. Treatment has been variable in approach and success. Cyriaxʹs proposed shoulder capsular pattern was external rotation most limited followed by abduction followed by internal rotation. This investigation was performed to determine if a consistent pattern of motion loss was present in subjects with idiopathic loss of shoulder motion. Methods. Repeated measurement of 25 (22 female) subjectsʹ bilateral shoulder patterns of motion were compared. The three-dimensional position of the scapula and humerus throughout active shoulder abduction, external rotation, flexion, internal rotation, and scapular plane abduction was evaluated with an electromagnetic motion capture system. Patterns of motion loss were determined for both shoulders. The proportions of peak shoulder motion to mean maximum non-involved shoulders abduction, external, and internal rotation were utilized to determine the pattern of motion loss. Findings. There was a significant difference in motion loss patterns between the involved and non-involved shoulders with the arm at the side. The internal rotation less than abduction less than external rotation pattern was demonstrated in 14 of 25 (56%) involved shoulders. No pattern was present in 14 of 21 (67%) non-involved shoulders. With the arm abducted, internal rotation was the most limited motion in 23 of 25 (92%) involved shoulders. Interpretation. The results did not support Cyriaxʹs proposed glenohumeral capsular pattern. Defining the pattern of motion loss in subjects with idiopathic loss of shoulder motion may assist in diagnosis and treatment.