[Osteosynthesis in dislocated femoral neck fracture (Garden 3 and 4). Long-term results and treatment concept].

The dislocated fracture of the femoral neck (Garden type 3 and 4) in the young patient is preferably treated by open reduction and internal fixation. In the period 1980-1989 we fixed 49 fractures with a dynamic hip screw, a 130 degrees-angled plate, screws alone, or by a valgisation osteotomy fixed with a 120 degrees-plate (Pauwels osteotomy). 30 fractures were reviewed after 66 months in average. We observed radiological signs of femoral neck necrosis in 9 patients, thereof 7 with symptoms, and radiological signs of osteoarthritis in 3 patients, two with symptoms. The possible factors causing these late complications are discussed. We advocate the immediate open reduction to evacuate the intracapsular hematoma into a slight valgus over-correction for stability. For the fixation we use 3 screws in good bone quality, the dynamic hip screw and the angled plate in osteoporotic bone often combined with an accessory screw for rotational stability. The functional long-term result was good or excellent in 70%. By avoiding technical errors this rate can be improved.