Translation of the glenohumeral joint with the patient under anesthesia.

This study was undertaken to determine glenohumeral translation in the anesthetized patient. Radiographically assessed humeral translation was measured in 18 members of a control group, 10 patients with anterior instability, and 10 patients with multidirectional instability. In the control group stress radiographs revealed anterior translation of 17% (percentage of the diameter of the glenoid from anterior to posterior), posterior of 26%, and inferior to 29% (percentage of diameter of glenoid from superior to inferior). In patients with anterior instability anterior translation was 29%, posterior translation was 21%, and inferior translation was 49%. In patients with multidirectional instability anterior translation was 28%, posterior translation was 52%, and inferior translation was 46%. Overlap in translation was seen between normal members and those with instability. The most practical method to grade anterior and posterior translation of the humeral head within the glenoid fossa involves a clinical assessment of where the center of the humeral head rests in reference to the glenoid rim.