[Aseptic necrosis of head of femur and disturbance of fat-metabolism type IIa after Fredrickson (author's transl)].

The history of aseptic necrosis of the head of femur is given. Following publication of osteonecrosis in hyperlipoproteinemia type IV after Fredrickson, now for the first time the relation between aseptic necrosis of the femoral head and the primary disturbance of fat metabolism type II is revealed. There exists a hypercholesterinemia, more exactly a hyperbeta-cholesterinemia. The subgroups type IIa and type IIb are explained. Type II is of particular importance since it produces early arteriosclerosis which demands early diagnosis, since this condition can be treated by drugs and diet. In the writers' opinion further differentiation of dys-and hyperlipidemiae in aseptic necrosis of the femoral head will enable us to define signs of disturbances of lipid metabolism. The group of "idiopathic" necroses of the femoral head will become steadily smaller. According to this basic concept the hypothesis might be put forward that this type of aseptic osteonecrosis is a late complication of a differentiated fat-metabolic disturbance.