We expected the motion fraction could be checked, with simple radiographic examination, according to the guide-line of fluoroscopic technique, and recovery of the function also could be correlated with the improvement of the motion fraction.

We measured the motion fraction of the glenohumeral and scapulothoracic movement using fluoroscope in 30-degree intervals of arm elevation in the scapular plane. The ratio of glenohumeral to scapulothoracic movement (thetaGH/thetaST) was 1.6 for the full range of motion in scapular plane. During arm elevation, scapular tilting from the coronal plane was decreased from 42 degrees to 20 degrees tilting as well as internal rotation (scapular extension). We also measured the motion fraction (thetaGH/thetaST) and functional recovery of the shoulder in 11 patients after operative treatment of the shoulder instability in 15 patients from December 1996 to August 1997.

We could find out a significant correlation between the recovery of motion fraction and shoulder function. These results would be applied in planing rehabilitation program after treatment of the shoulder instability.

The measuring technique of glenohumeral to scapulothoracic movement (thetaGH/thetaST) with fluoroscopy could be applied to the simple radiographic measurement at the out-patient clinic in order to identify the pathology and recovery of shoulder motion after treatment