Recurrent anterior shoulder dislocation caused by a midsubstance complete capsular tear.

BACKGROUND

A midsubstance complete capsular tear is one of the well-known causes of anterior glenohumeral instability. However, its prevalence and clinical picture have not been well elucidated. The purpose of this study was to examine the prevalence of isolated complete capsular tears and to assess the clinical features as well as the results of surgical treatment of recurrent anterior glenohumeral instability caused by such tears.

METHODS

Three hundred and three shoulders underwent surgery to treat recurrent anterior glenohumeral instability at our institution during a five-year period. Twelve (4.0%) of these shoulders had an isolated complete capsular tear as the main pathological condition. Those twelve patients (nine male and three female) were the subjects of the present study. The average age at the time of the operation was twenty-five years. Patient age; the cause of the initial dislocation; the position of the arm at the initial dislocation; and the findings of the preoperative physical examination, of computed tomographic arthrography, and at surgery were assessed. Eleven patients underwent arthroscopic capsular repair, and one was treated with an open capsular repair.

RESULTS

The twelve patients either did not have a Hill-Sachs lesion or had a chondral indentation-type of Hill-Sachs lesion. When assessed with arthrography, the Hill-Sachs lesions were small compared with those in shoulders with an isolated Bankart lesion and, interestingly, they were quite similar in size to those seen with humeral avulsion of the inferior glenohumeral ligament. The average Rowe score for the twelve patients improved from 30.4 points preoperatively to 90.4 points at an average of thirty-one months postoperatively.

CONCLUSIONS

The prevalence of isolated complete capsular tears causing recurrent glenohumeral instability was 4.0% (twelve of 303). These tears were associated with either a small or no Hill-Sachs lesion. We believe that a complete capsular tear should be recognized as one of the essential lesions causing recurrent anterior shoulder dislocation. Arthroscopic examination and repair can provide effective treatment.