[Shoulder arthrodesis. Indications, techniques, results, complications].

Besides the paralysis of shoulder muscles, large rotator cuff tears beyond repair, persistent shoulder instability with repeat dislocations and resection cases are recent indications for shoulder arthrodesis. The fusion of the shoulder is particularly useful since, despite immobilization of the glenohumeral and acromiohumeral joints, no loss of function is experienced; on the contrary, in many cases an increase of active total mobility may occur. According to the functional outcome, the majority of reports vary between 30 degrees and 90 degrees of active abduction and forward flexion with a mean value of about 60 degrees The most generally accepted arthrodesis position is 20 degrees -40 degrees abduction, forward flexion and internal rotation in relation to the trunk. This position results in a maximum development of muscle power and ensures that the arm will rest comfortably at the side, and that the scapula will not protrude. This also allows the hand to reach the head and facial region. The literature is not confined to any uniform type of arthrodesis and it would appear that the techniques and configurations of material vary considerably. A general advantage of any one particular form of arthrodesis, and the use of plates, screws or external fixators, cannot be deduced. Pseudarthrosis appears to be less frequent in cases of plate arthrodesis compared to screw arthrodesis. However, the application of plates more often results in infections, postoperative fractures of the humerus and the necessary removal of material. Screw arthrodesis is more beneficial in that the exposed area to be operated is smaller than in plate arthrodesis. Postoperative immobilization is more time consuming and, therefore, constitutes one of the disadvantages of screw fixation.