[The extraarticular proximal tibial fractures].

Operative stabilization of proximal tibial fractures by use of conventional osteosynthesis is still problematic. The choice of the osteosynthetic treatment is strongly influenced by the situation of the surrounding soft tissue. Additional problems in this particular location may occur with malalignment in the fracture site after operation. Primary intraoperative malalignment may occur due to dislocating muscle forces or to the operative approach itself. Secondary dislocation is mainly due to the unstable fixation of the proximal fragment by the implant. Today many different implants with specific biomechanical properties are available. Each system requires a particular operative technique and can lead to individual implant-related problems. The new angle stable implant systems (e. g. LISS = "less invasive stabilization system"), offer significant advantages over conventional plate osteosyntheses and external fixation systems. Improvement of the geometry of standard intramedullary osteosyntheses and introduction of angle stability in the proximal interlocking screws (PTN = "proximal tibial nail") seemingly make this system the optimal solution, concerning biomechanics. On the background of our own clinical experiences and biomechanical investigations, the article discusses solutions for this particular problem.