[The therapy for pyogenic coxitis and its stabilisation with the fixateur externe (tubular system) (author's transl)].

The treatment of the destructive, unstable state of infection on the hip often takes an unfavourable course, because alloarthroplastic techniques are ruled out on principle, while the hip arthrodesis itself creates biomechanical problems under the incomparably more favourable aseptic conditions. The protracted trimming arthrodesis with immobilisation by pelvic plaster cast remains precarious with regard to the painful stress and the sedation of the infection, and it always includes the danger a damage causing immobilisation of the knee joint. The jointparts destructed by the infection are equivalent to an infected pseudarthrosis; for its stabilisation the fixateur externe is indicated, by analogy to the approach used on the extremities. The biomechanical problems are similar to those occuring with the internal fixation of hip arthrodesis: neutralisation of dislodging forces on the long leg lever, reliable anchorage of the means of osteosynthesis on the pelvis and axial compression on the broadest possible contact surfaces of the anthrodesis. A special installation of the fixateur externe (tubular system of the ASIF) is pointed out, which meets almost all requirements. The external osteosynthesis joins lateral ilium and femur shaft, compressing the hip area. For securing the stability it is necessary to include both of the iliac crests and a diagonal brace in the outer construction. The external fixation for stabilising the hip represents a large-scale technique which, by its nature, is inferior to internal osteosynthesis. But for the treatment of active pyogenic coxitis neither the arthrodesis by copra-head-plate nor the screw joint in connection with intertrochanteric osteotomy is suited. The advantages in contrast to the classical therapy with pelvic plaster cast are obvious. The operating method is explained on a model and presented in a casuistry on 3 people operated on so far. If the head-neck-segment is lost completely after septic head necrosis, a careful debridement and the Girdlestone-plastic usually lead to an infection sanitation, but mostly at the cost of an unstable hip on the considerably shortened leg.