We studied retrospectively a consecutive series of 547 shoulders in 529 patients undergoing operation for instability. In 41, the cause of instability was considered to be lateral avulsion of the capsule, including the inferior glenohumeral ligament, from the neck of the humerus, the HAGL lesion. In 35, the lesion was found at first exploration, whereas in six it was noted at revision of a previous failed procedure. In both groups, the patients were older on average than those with instability from other causes. Of the primary cases, in 33 (94.3%) the cause of the first dislocation was a violent injury; six (17.4%) had evidence of damage to the rotator cuff and/or the subscapularis. Only four (11.4%) had a Bankart lesion. In patients undergoing a primary operation in whom the cause of the first dislocation was a violent injury, who did not have a Bankart lesion and had no suggestion of multidirectional laxity, the incidence of HAGL was 39%.

We have analysed the Constant-Murley (1987) assessment for 25 patients with shoulder pathology. We found the score easy to use, with low inter- and intraobserver errors, but sufficiently imprecise in repeated measurements to give concern in its use for clinical follow-up of patients.

We have calculated 95% confidence limits for a single assessment to be within 16 to 20 points in most cases. In addition, we found that all our subjects with instability as their main problem scored within five points of the maximum; this suggests that the scoring method may need to be revised for use on these patients.