Patent GB-1416042-A (GB)
Title: Artificial hipjoint
IPC: A61F2/30
Filed: 1973-01-10
Abstract: 1416042 Artificial hip joints UNITED STATES SURGICAL CORP 10 Jan 1973 [13 Jan 1972] 1355/73 Heading A5R An artificial hip joint comprises: an acetabulum prosthesis 10 having a head 13 which includes a plurality 'of outwardly extending blades 14, 16, 18, 20 and at least one detachable insert 30 defining a socket 12 which is more than a hemisphere; and a prosthesis 22 for the head of the femur, having a tapered pin 24 adapted to be driven into the bonemarrow channel of the femur, and a hip ball 28 which is positioned on a curved neck 26 and movably located within the socket. The inserts 30 are tightly but removably fixed in the head 13 with the whole of their outer surfaces in contact with the head by means of a flexible ring 92 positioned within a groove 90 and a channel 88 respectively provided in the inserts and in the head 13. Insertion and removal of the ring 92 is facilitated by the provision of an entry slot 96 and an entry slot 94, Fig. 2 (not shown), in the inserts and head respectively. Removal and insertion of the ring are further facilitated by the provision of an extension well 108 and by the provision of an aperture in an enlarged end of the ring. In a modified form a second set of entry slots are provided for use with two half-rings. The base 62 of the curved neck is eccentrically positioned with respect to the central axis 64 of the pin and is joined to a shoulder 60 having a lower surface 68 that, in use, rests on the femur. In use, bone tissue grows through slots 72, 74 provided in the pin 24 and through notches and holes provided in the blades 14-20. A rod 78 which may be provided is adapted to pass through a hole drilled in the greater trochanter. A collar 80 may be provided for insertion into the femur and has a flange portion 82 and a sleeve portion 84 having holes 86. The inserts (30), Fig. 16 (not shown), may be prevented from rotating within the head (13) by the provision of a projection (140) which is received in a depression (142) in the head. In Figs. 19, 20 (not shown), a single or two-piece insert is screwed into the head and heated to enable insertion of a hip ball. The means for preventing rotation of the femur head prosthesis in the femur take various forms. In Fig. 5, (not shown), a fin (110) integral with the pin (24) engages a slot cut in the femur. In Fig. 9, (not shown), the pin (24) has knife edges (118) for cutting into the femur. In Fig. 9 (not shown), a sharpened spade end (120) extends from the pin and has blades (124) for engaging the femur. The pin (24) of Fig. 10, (not shown), has a key (126) for fitting in a slot (112) cut in the femur. In Fig. 13, (not shown), a rod (138) located along the pin (24) is received in a slot (112) cut in the femur. In the form of Fig. 14, (not shown), a square member (131) is integral with the pin (24). The shoulder (60) of the embodiment of Fig. 15, (not shown), has a flattened side (61) for abutting with the greater trochanter (63). The embodiments of Figs. 17 and 18, (not shown), have removable hip balls. In Fig. 17, a holding pin (146) extends through the hip ball and through the neck.