| 摘要 |
PURPOSE:To make it possible to move smoothly without corrosion after using for a long time by placing uniformly rotating balls brought into contact with both surfaces of both spheres between gape of an outer sphere and an inner sphere which is fixed with an inner sphere holding ring and a fixing ring both located outside thereof. CONSTITUTION:An outer sphere 2 of an artificial bone head 1 and an inner sphere 4 of a stem part 3 are fixed by the outer sphere 2 and an inner sphere holding ring 5 and a fixing ring 6 consisting of high density polyethylene or polyacetal on the outer sphere 2. Rotating balls 8 brought into contact with the surfaces of the outer sphere 2 and the inner sphere 4 and consisting of the same material as those of both spheres 2 and 4 are placed uniformly in a gap 7 produced between the outer sphere 2 and the inner sphere 4 and the rotating balls 8 are held by means of a ring-shaped holder 9 fitted on the outer face of the inner sphere 4 and holding a freely-rotating supporting balls 10 and are made thereby in a body with the outer sphere 2. It is thereby possible to keep a smooth movement of the artificial bone head 1 after using for a long time. |
