Patent ID: 8114166
Filing Date: 2012-02-14
Classification: A61B,A61F

Abstract:
1. A retentive and removable trial bearing insert for use with a total hip replacement joint which includes a dual mobility or bipolar prosthetic cup which has a part-spherical outer bearing with a part-spherical inner bearing surface which engages a part-spherical bearing head on a femoral stem comprising a part-spherical trial inner bearing element dimensioned to replace the part-spherical bearing insert and which includes an outer bearing surface and an inner bearing portion defining a wall there between the wall having a pair of diametrically opposed openings and an expandable retaining element mounted within the inner bearing portion having an outer tapered surface, an inner surface of the wall having a recessed circumferential tapered portion tapered outwardly from an open end of the trial bearing insert and the expandable retainer insert having two lugs with one lug extending through each opening of the pair of openings in the wall which expandable retaining element has an inner surface which engages the bearing head of the femoral stem or a trial bearing head thereof to hold the trial bearing element beyond the outer bearing surface in place thereon, said expandable retaining element lugs extend through the openings in the wall of the trial bearing element for external operation and are moveable within each opening in the wall in an axial direction of the part-spherical trial inner bearing element from a first contracted position to a second expanded position, said expandable retaining element has an inner surface in the first contracted position which engages said bearing head or trial bearing head at a diameter which is less than the maximum diameter thereof and the inner surface in the expanded position has a diameter greater than the maximum diameter of the head and is spaced from the head.