Surgical treatment of chronic acromioclavicular joint dislocation by modified Weaver-Dunn procedure.

We present our technique for surgically treating Tossy III acromioclavicular joint dislocation, discuss the indications for various procedures, and evaluate our postoperative results. We operated on 17 patients suffering from chronic acromioclavicular instability after such dislocation using a modified Weaver-Dunn procedure, in which there is no lateral clavicular end resection, the coracoacromial ligament graft is sutured to the inferior part of the clavicle by transosseal sutures, and a Bosworth coracoclavicular screw is used to protect the graft postoperatively for 8 weeks. After a mean of 37 months we evaluated shoulder function by the Constant score and the subjective and radiological results. Mean Constant score was 91.9% (74-100%); it was 80-90% in 5 patients and above 90% in 11. One patient had screw loosing after the operation and suffered partial loss of reduction and discomfort during shoulder loading. All patients but one returned to work, and all but one have returned to their preoperative activity at the same level. Subjectively, there were 11 excellent and 6 good results. Compared to the contralateral uninjured side, radiography showed anatomical reposition in the vertical plane in 9 cases, slight loss of reduction in 6 (difference in the distance between the inferior border of the acromion and the clavicle is 2-4 mm), and partial loss of reduction in 2 (4-8 mm). We recommend the modified Weaver-Dunn procedure for surgical treatment of chronic, Tossy grade III acromioclavicular joint dislocations as it provides good functional and subjective results. Our modification is indicated mainly for young patients because posttraumatic arthrosis occurs more frequently in elderly patients, making clavicular end resection necessary.