[Endoprosthesis of the shoulder joint designed by the authors - surgical technique.]

Endoprostheses of the shoulder joint are nowadays already standard procedures in the surgical repertoir of orthopaedic and traumatological departments. Indication for the operation are degenerative diseases with destruction of the articular surface, non-reconstructible fractures of the upper end of the humerus, in particular in elderly patients and tumours in the area of the proximal portion of the humerus. The main cause of inadequate function of endoprostheses of the shoulder joint is insufficiency of the rotator cuff. This may be due either to its primary destruction by the basic disease (e. g. rheumatoid arthritis) or imperfect reconstruction during surgery. The majority of authors use during reconstruction of the rotator cuff a simple procedure, i. e. suture to the proximal portion of the endoprosthesis. In some instances the implementation of the suture is difficult or there is the risk the stiches will cut through during rehabilitation. Favourable experience with reconstruction of the rotator cuff during non-anatomical reconstruction of fractures of the proximal humerus by screwing of the insertion lamellae of the greater and lesser tubercle made the authors try to use this principle in the construction of a new type of endoprosthesis, which is described in detail in the submitted paper. Subsequently the authors describe also differences in the surgical technique during implantation of the endoprosthesis in patients with degenerative diseases and in traumatological indications. In their opinion the advantage is that in traumatic indications of replacement of the shoulder joint the suggested implant makes reliable and relatively easy fixation of both tubercles with insertions of the rotator cuff to the endoprosthesis possible and simultaneously also attachment to the fragment of the diaphysis. In fragments of the greater tubercle this can be achieved by the use of a clawed splint which is fixed by one screw inserted via the corticalis of the diaphysis into the stem of the endoprosthesis. This ensures the stability of the endoprosthesis in the proximo-distal direction as well as against rotation. The fragment of the lesser tubercle is fixed by one screw to the body of the endoprosthesis. The authors assume that reconstruction of the rotator cuff and at the same time stabilization of the shank of the endoprosthesis by one screw and a clawed splint differs fundamentally and is a new approach to the solution of this very complicated problem. Despite the initial clinical experience the authors are aware of certain technical shortcomings of the implant and instrumentarium and continue to work on their elimination. Key words: endoprosthesis of the shoulder joint, reconstruction of the rotator cuff.