[An experimental study on the influences of artificial socket upon articular cartilage of the femoral head (author's transl)].

In order to investigate the influences of artificial socket made of stainless-steel, pure titanium, high-density polyethylene (HDP), and polycrystal ceramics upon the articular cartilage of the femoral head, experimental artificial sockets were developed. This artificial socket was inserted into the hip joint in a dog, and the changes in the articular cartilage of the femoral head were studied at varying intervals after insertion of the socket. The results revealed that both the stainless-steel and the ceramic sockets caused slight atrophy and degeneration in the articular cartilage of the femoral head since one month after the operation, and these changes were increasingly more appreciable as time advanced. Any changes were hardly noted in the articular cartilage of the femoral head by titanium socket at the end of one month after the operation, whereas the HDP socket caused substantial changes. At the end of one year after the operation, marked degeneration was noted in the articular cartilage of the femoral head by socket made of stainless-steel, titanium, and HDP, and also the femoral head developed deformity. On the basis of the scanning electron microscopic findings on the surface of the articular cartilage of the femoral head affected by each of these artificial socket, and of the metal microscopic examinations of the surface of the artificial sockets, and furthermore on the basis of the findings of gradual deformation of femoral heads due to the artificial sockets, it was shown that articular cartilage of the femoral head was mainly influenced in the case of metallic socket and that both sides of the artificial socket and the articular cartilage of the femoral head were worn out in the case of HDP socket. The ceramic socket was found cracked, developing a loosening in some cases. In summary, it was concluded that the articular cartilage of the femoral head is affected by the artificial socket at a relatively early stage after its application despite materials of the sockets.