[The value of ultrasound in evaluating instabilities of the glenohumeral joint].

In a prospective study we evaluated diagnostic ultrasound investigation for shoulder instabilities. We measured the passive aptranslation In 150 healthy persons in relation to the dorsal glenoid as well as the inferior subluxation in relation to the acromion. After establishing normative datas we measured 23 patient with unidirectional instabilities and 34 with multidirectional instabilities. The humeral head position of a normal joint is 8 to 10 mm dorsally to the glenoid. In the control group the anterior translation of the dominant shoulder is significantly higher as in the nondominant shoulder (student-t-test; p less than 0.0045). Patients with anterior instabilities showed a significant increase of anterior translation in the injured shoulder (student-t-test; p less than 0.0001). In comparison with the control group there is a significant increase of downward subluxation in patients with multidirectional instabilities (chi 2 alpha less than 0.05). In habitual or voluntary dislocations the relation of the humeral head to the glenoid can be judged statically and dynamically. Secondary signs of dislocation (Hill-Sachs lesions, joint effusion) are evident.