Fracture of the middle third of the clavicle and dislocation of the acromioclavicular joint. A report of four cases.

Fracture of the middle third of the clavicle and dislocation of the acromioclavicular joint occur commonly as separate injuries. The combined injury to the ipsilateral shoulder is quite rare, however. Mauro described such a case with a delay in diagnosis due to the unique anatomical features of the injured area. We report the cases of four patients, two men and two women, nineteen to thirty-six years old, who sustained this combined injury. Our four patients were seen between 1984 and 1989, and two of them (Cases 3 and 4) had initial treatment at graded according to the system of classification of Rockwood (Table II)’5’8.Three ofthe fourpatients (Cases 1,2, and 3) had a Type-IV dislocation of the acromioclavicular joint: hence, the distal end of the clavicle was displaced posteriorly into the substance of the trapezius muscle (Figs. 1-A and 1-B). In these three patients, the injury was treated operatively by internal fixation with acromioclavicular transfixation pins3”3 or a special coracoclavicular cancellous-bone screw (Fig. 1-C)48’6. Because of a six-week delay in the diagnosis of the dual