Abstract: An artificial hip joint of the type wherein a metal stem is fitted into the tapered hall of a ceramic stem head via a tapered cone in the stem, the hip joint being characterized in that the tapered stem engages the tapered hall in the deeper portion of the tapered hall, whereby the compression strength (fracture load) of the stem head is improved. Deep engagement of the tapered stem within the tapered hall is accomplished by, for example, making the angle of the taper of the tapered cone slightly smaller than that of the tapered stem. Preferably, the angle of taper of the tapered cone is smaller than that of the tapered hall by about 40 minutes or less. In addition, the diameter at the base of the hall is enlarged to form a cavity.

Abstract: In an artificial hip joint, in which a tapered cone of a metallic stem is inserted into a tapered hole of a ceramic stem head to be fixed, a truncated conical sleeve having a thickness of 50 .mu.m to 5.0 mm is compressedly held between a wall surface of the tapered hole and an outer circumferential surface of the tapered cone such that they are taperedly engaged with each other. With this artificial hip joint, an increased strength of the stem head, easy production, miniaturization, increased useful life time, safety in use, and the protection of the tapered cone are achieved.

Abstract: Method and device for supplying electric current to ceramic heaters comprising heating resistors embedded in ceramic sintered bodies, being characterized in that direct current is supplied from a direct current supply circuit as the first current supply step and the direction of the direct current supplied to the heating resistors at the first current supply step is reversed by a switching circuit or alternate current is supplied as the second current supply step in order to eliminate or considerably reduce cracking of the ceramic sintered bodies of the ceramic heaters when the heaters are repeatedly used for a long time at high temperatures.