Glenohumeral motion after complete capsular release.

The range of glenohumeral motion is primarily limited by the joint capsule. If the capsule is contracted, greater restriction in glenohumeral motion is exhibited. Release of a tight capsule has been an effective means of managing refractory stiffness of the glenohumeral joint. The effect of a complete capsular release on glenohumeral kinematics has not been previously studied in a cadaver model. Elevation, rotation, and translation of eight cadaveric glenohumeral preparations were studied before and after complete capsular release. As the intact joint was positioned near the limits of motion, glenohumeral torque rose rapidly with relatively small concomitant increases in elevation and rotational angles. Notable torque, due to tension in the capsule or cuff, ensued only after glenohumeral elevation reached approximately 80% of maximal range. After complete capsular release, maximal elevation increased on average 15%, yet retained definitive endpoints due to residual tension in the rotator cuff. Axial humeral rotation with an intact capsule decreased as maximum elevation approached, especially at elevation angles greater than 60 degrees. Maximum internal rotation was less than external, for all planes except +90 degrees. After complete capsular release, the greatest net gains for external rotation tended to be in the posterior scapular planes, whereas gains for internal rotation tended to be in the anterior scapular planes. Maximal translation in an intact vented capsule was 21 mm, 14 mm, and 15 mm in the anterior, posterior, and inferior directions, respectively. After complete capsular release, translation increased in all positions with maximal anterior, posterior, and inferior translations of 28 mm, 25 mm, and 28 mm, respectively. In general, relative gains in translation were greater in planes posterior to the scapula and at extremes of the range of motion. Although large glenohumeral translations were measured, no preparation could be dislocated before or after complete capsular release. Complete capsular release significantly increased glenohumeral range of motion and translation. The intact rotator cuff myotendinous units serves to limit the range of motion and translation after all capsuloligamentous attachments are rendered incompetent by complete capsular release.

The humeroscapular motion interface.

Motion between the humerus and scapula commonly is described as glenohumeral motion. However, humeroscapular motion occurs at two distinct sites. In addition to the motion at the diarthrodial glenohumeral joint, movement occurs between the proximal humerus and related structures and the surrounding sleeve of structures, including the acromion, deltoid, coracoid, coracoacromial ligament, and the muscles attached to the coracoid. This site of nonarticular shoulder motion is defined as the humeroscapular motion interface. Nonarticular humeroscapular motion can be documented and measured using standard magnetic resonance imaging techniques. The maximum average interfacial motion using axial images was 29.1 mm, which occurred at the level of the maximum diameter of the humeral head. Interfacial motion varied depending on the site measured. If pathologic conditions such as adhesions secondary to trauma or surgery interfere with or obliterate this space at sites of significant sliding motion, overall shoulder motion will be limited. Successful treatment of shoulder stiffness related to humeroscapular restraints is likely to require restoration of the normal sliding motion at the humeroscapular motion interface, in addition to resolving restraints affecting the glenohumeral joint motion.

Adhesive capsulitis of the shoulder joint: usefulness of dynamic sonography.

We studied the value of dynamic sonography in adhesive capsulitis of the shoulder joint in patients with clinically suspected frozen shoulder. The sonographic criterion of adhesive capsulitis was continuous limitation of the sliding movement of the supraspinatus tendon against the acromion of the scapula. Arthrography was regarded as a gold standard in the diagnosis of adhesive capsulitis against which the sonographic results were compared. Among 23 patients with arthrographically documented adhesive capsulitis, sonographic examination showed limitation of movement of the supraspinatus tendon in 21. This sonographic sign therefore has a sensitivity of 91%, a specificity of 100%, and an accuracy of 92% for detecting adhesive capsulitis, making dynamic sonography a reliable technique for the diagnosis of this condition.