Osteosynthesis with wires and cerclages is the operative technique of choice in case of recent or old breaking of acromio-clavicular joint. In case of an old lesion of the acromio-clavicular joint syndesmoplasty should be performed only if direct suture of the ligaments is no longer possible. The so-called "allo-ligament" proved to be a failure because of the high rate of infections. The "Kirschner wires" should have a thickness of at least 1.5 mm. To avoid stiffness of the operated shoulder there should be an early active functional treatment. The removal of the osteosynthesis material should be performed only after complete healing of the ligaments (3-4 months postoperatively).