Purpose of the study: Shoulder arthroplasty in traumatological indications has a considerably worse prognosis than when the indication is osteoarthritis or rheumatoid arthritis. The problem lies in the technique of rotator cuff reconstruction and the restoration of adequate bio-mechanical properties of the shoulder joint. In this study, the difficult reconstruction of four-part fractures of the proximal end of the humerus was improved by the development of a new type of shoulder joint endoprosthesis.
Material and methods: Our endoprosthesis permits fixation of bone fragments of the greater and lesser tubercles to the shaft and to the diaphyseal fragment by using screws or a toothed plate designed for this purpose and produced in various shapes. In addition to the modularity of the head, the endoprosthesis has a component facilitating better recovery of biomechanical properties of the proximal end of the humerus, and this is a variable neck of the prosthesis. The modularity of the neck makes it possible to adjust the colodiaphysal angle and to adjust the head in relation to the stem in eight different positions. The shoulder replacement described, produced in two modifications by ProSpon (Czech Republic) and MIL (France), was used in surgical treatment of 43 acute fractures and 33 cases of post-traumatic destruction. The clinical outcome was assessed using the Constant rating score.
Results: In patients with acute trauma of a shoulder, an average of 59 points (range, 23-82) was achieved. The average maximal elevation was 88 degrees, with a range of 40 to 140 degrees. In 25% of the patients, no postoperative pain was present; mild pain at strain was reported by 73% of the patients and pain limiting the arm's activity by 3%. In patients with post-traumatic destruction of a shoulder, the average value vas 53.5 points (range, 20-88) and the average maximal elevation was 85 degrees (range, 30-130). No postoperative pain was reported by 36%, mild pain at strain was recorded in 52% and activity-limiting pain in 12% of the patients.
Discussion: The currently reported views are in agreement with our opinion that, at present, every method of shoulder replacement should enable the surgeon to achieve, as easy and reliably as possible, the reconstruction of fragments with the attachments of the rotator cuff. With our system, shoulder arthroplasty for the reconstruction of the proximal humerus, using the supplementary fixation components described, allowed us to treat even the most serious cases of traumatic destruction of the proximal humerus.
Conclusions: To facilitate the treatment of trauma in displaced, three- or four-part fractures of the proximal end of the humerus, a new technique of reconstruction with the use of an endoprosthesis designed by us was developed. Fixation and reconstruction of fragments of the greater and lesser tubercles are carried out with screws and a special toothed plate that provides good fixation of the fragments to the stem. Compared with the current method of fragment fixation with simple suture, this technique offers an easy way of restoring the biomechanical properties in the region of the proximal end of the humerus and improves the stability of osteosynthesis. This aids in early mobilization and functional therapy of the patient, which results in a better overall outcome of the treatment.