[Arthroscopic evaluation of the mobility of the meso-acromion].

Objectives: Failure of fusion of the secondary centers of ossification of the acromial apophyses is a pathology that should be included in the differential diagnosis of shoulder pain and subacromial impingement syndrome. Mobility of the meso-acromion is of particular importance in choosing the appropriate treatment. This study presents a new arthroscopic method to evaluate the mobility of os acromiale.

Methods: We presented the arthroscopic evaluation and surgical treatment of three women (mean age 43.3 years; range 34 to 53 years) with shoulder pain and a radiographically confirmed meso-acromiale. The Neer and Hawkins impingement signs were positive and palpation over the acromion gave rise to pain. Axillary radiographs showed a meso-acromion in all the affected shoulders. Magnetic resonance imaging showed a rotator cuff tear in one patient. During arthroscopic examination the motility of the meso-acromion was dynamically observed in the subacromial region and the rotator cuff tear was repaired. Acromioplasty was not performed. Following removal of pseudarthrotic areas, the mobile meso-acromion was fixed with a cerclage wire, two cannulated screws and bone grafting, followed by a tension-band configuration. The mean follow-up was five years (range 3 to 6 years).

Results: Union occurred in all the patients. None of the patients had shoulder pain at rest or during activities. When compared with the normal side, the range of motion and the strength of the shoulder were normal in all the patients, with Constant scores being 89, 96, and 98, respectively.

Conclusion: Identification of the type of os acromiale is important for the treatment plan. The meso-acromion is particularly important because of its greater size and its role in narrowing the subacromial space. It is necessary to determine whether the meso-acromion fragment is mobile. Dynamic arthroscopic examination offers significant help in this respect.