Os acromiale associated with tear of the rotator cuff treated operatively. Review of 33 patients.

Os acromiale is a rare anatomical abnormality and treatment is controversial. Our retrospective study analyses the outcome of excision, acromioplasty and bony fusion of the os acromiale when it is associated with a tear of the rotator cuff. After a mean follow-up of 41 months, 33 patients were radiologically and clinically assessed using the Constant score. The surgical procedure was to repair the rotator cuff together with excision of the os acromiale in six patients, acromioplasty in five, and fusion in 22. Of the 22 attempted fusions seven failed radiologically. The Constant scores were 82%, 81%, 81% and 84% for patients who had excision, acromioplasty, successful fusion and unsuccessful fusion respectively. There were no statistically significant differences. We conclude that a small mobile os acromiale can be resected, a large stable os acromiale treated by acromioplasty and a large unstable os acromiale by fusion to the acromion. Even without radiological fusion the clinical outcome can be good.

Influence of T-shift capsulorrhaphy on rotation and translation of the glenohumeral joint: An experimental study.

To evaluate changes in the response of capsuloligamentous restraints to translatory forces and rotation torques caused by experimental capsulorrhaphy (T-shift modification of Bankart repair), eight cadaveric shoulders were tested. Measurements were taken in intact and vented specimens, after severance of the anterior capsule at the glenoid rim (creating an artificial Bankart lesion), T-shaped incision of the anterior capsule, and refixation of the capsule (with a standard Bankart procedure) combined with tightening by T-shift. Rotation torques and translatory forces were applied in different positions of abduction with a specifically designed mounting apparatus that had four degrees of freedom. Dynamic and static measurements were performed with a tracking sysem that had six degrees of freedom. T-shift capsulorrhaphy restored the resistance of the capsuloligamentous restraints to translatory forces in all directions. This restoration was confirmed when we compared these results with data obtained from intact joints. No significant alteration of the centering mechanism resulting from rotation torques was observed, although the extent of external and internal rotation was remarkably decreased. This T-shift modification seems to produce a symmetric reduction of the volume of the capsule without significant displacement of the humeral head.