[Problems in osteosynthesis of patella fractures with the AO tension belt and consequences for new implants. The XS nail].

The eccentric ventral AO tension belt system represents the standard therapy of fractures of the patella. This often leads to unsatisfying results. Relating to Klute and Meenen [10] and the results of our own retrospective study, expressed as a percentage, 5-34% (own results 12.4%) have extremely poor treatment outcome, 23-60% (39%) end in deficiencies of bending, and there are 51-79.5% (65.7%) with subjective complaints after patella osteosynthesis. The disadvantages due to the eccentric tension belt position and the impossibility of applying the tension belt directly to the bone surface are abolished with the development of the XS nail. Due to its central position, constant compression of the entire fracture surface is provided. This is valid for all tension-stressed fractures such as those of the patella and olecranon. In synthetic patellae [5] standardized stress testing with changing tension up to 500 Newton was carried out. The XS nail was compared with the AO tension belt osteosynthesis after osteotomy and osteosynthesis in synthetic patellae. The XS nail was superior to the tension belt for all tests and therefore can be applied to all types of fractures where tension stress exists. We repaired the first 15 patella fractures with the XS nail. In 13 of 15 cases, full load of the injured leg was possible (for stairs a plaster splint was used). The experimental patella tests and first clinical results with the XS nail osteosynthesis after patella fracture confirm the new type of osteosynthesis, and functional treatment with loading seems possible.