[Our Initial Experience with Radial Head Replacement].

PURPOSE OF THE STUDY A single treatment procedure for multi-fragmented non-reconstructible radial head fractures has not been established as of yet. One of the available treatment methods can be the implantation of an endoprosthesis, but there is no consensus in available publications. We therefore decided to trial their use and to obtain our own experience. This study includes the evaluation of the outcomes of treatment at one year postoperatively. MATERIAL AND METHODS Our group included eight patients (six men and two women with the mean age of 46.1 years, ranging from 24 to 80 years) with an implanted ExploR® (Biomet, U.S.A.) radial head endoprosthesis. The radial head fractures were of three to six fragment type, in six cases there was an associated dislocation. In one case, there was a concomitant diaphyseal fracture of the ulna which was stabilised using the Würzburger intramedullary nail (TRUE-Instrumente GmbH, Germany). The surgical approach through Kocher's interval was used in all cases. Fixation using a plaster splint from metacarpophalangeal joints up to the shoulder was applied postoperatively for a period of two to three weeks in all patients. RESULTS The assessment was carried out on average at 13 months (range 12-15 months) after the surgery. The mean elbow flexion was 7.5° to 136.9°, forearm supination was 0° to 86.3° and forearm pronation was 0° to 80.0°. The elbow joint maintained its stability in all cases. Neurological deficit did not develop in any of the patients. The DASH score reached the mean value of 11.2. The mean value of the Mayo Elbow Performance Score (MEPS) was 92.5. Radiological signs of implant loosening were observed in three cases. In two of these cases, bone resorption occurred surrounding the stem of endoprosthesis. In two patients, heterotopic ossification were found and in one case, an oversized endoprosthesis head was implanted. No recurrent elbow dislocation was seen in any of the patients. DISCUSSION The application of radial head endoprosthesis is indicated for comminuted radial head fractures and concurrent ligamentous injuries (fracture-dislocations, terrible triad, Essex-Lopresti injuries). Equally good functional outcomes may be achieved with the use of an endoprosthesis as by osteosynthesis. The complications of arthroplasty tend to be late, at ten or more years postoperatively. Further follow-up of our patients will be necessary, along with a further expansion of our group of patients. Complications may be prevented with the use of longer-stem implants and more up-to-date cemented bipolar endoprostheses which, according to recent studies, achieve equally good functional outcomes and reduce the number of necessary revision surgeries - implant removal in particular. CONCLUSIONS In treating the comminuted radial head fractures, the implantation of endoprosthesis helps to achieve a quick restoration of the elbow joint function along with good functional outcomes and prevents instabilities in case of associated ligamentous injuries. A basic precondition for successful treatment is the choice of an adequate size head. The radiological signs of stem loosening do not necessarily have to affect the functional outcomes. Key words: fracture, radial head, endoprosthesis, Kocher approach.