Prevention of subluxation of ball-and-socket hip prosthesis - involves split or multi-segment ring surrounding equator of ball and screwing into threaded part of socket

摘要

The hip joint prosthesis incorporates a ball and socket joint which includes a safety ring (3c) to keep the ball (2) from falling out of the socket (1a). The ring may be split or divided into two halves so that it can be assembled onto the ball It fits onto a diameter of the ball and the ball cannot slide out when the ring is screwed into the socket. There is a female thread (6) on an enlarged portion of the inside of the socket accommodating the ring. There are cutouts (9) in the top surface of the ring to be gripped by a turning tool. Pegs (13) in blind bores (14) help to hold the ring segments together. Once the ring has been screwed in, a grub-screw (8) locks it in place. USE/ADVANTAGE - Secure locking of ball-and-socket joint on hip prosthesis to stop ball falling out of socket.