Precision hip joint replacement method

Claim 1

A precision hip joint replacement method involving a metallic femoral surface replacement prosthesis and a metallic acetabular surface replacement prosthesis for a femur having a main body portion and a ball or head coupled to the upper end of the main portion of the femur by a neck, said head and neck having a center and a central axis, said femoral head having an outer surface and an extreme outer end, and said prosthesis having a lower edge, said method comprising the steps of: a.) forming a hard metallic spherical surface replacement prosthesis, with an extent slightly greater than a hemisphere, and with a central tapered stem; b.) forming both an entirely metallic acetabular socket prosthesis and said metallic surface replacement femoral head prosthesis with a high degree of spherical accuracy and tolerances, but with slightly increased spacing tolerance at the equatorial zone of each said prostheses; c.) mounting a guide pin centered on the femoral ball, or head, and extending toward the center of the neck joining the ball to the upper end of the main portion of the femur; d.) using a feeler gauge to check the alignment of the guide pin with the axis of the femoral neck; e.) relocating the pin to the center of the axis of the femoral neck using an apertured relocation guide; f.) reaming the outer surface of the femoral head to a cylindrical configuration using the centrally mounted pin as a guide; g.) mounting a saw cutoff guide extending around the femoral head, with said saw cutoff guide having a plurality of laterally extending slots with a lateral guide pin extending from said head through a selected one of said slots, to axially locate said cutoff guide; h.) using a saw and said cutoff guide, cut off the extreme outer end of the femoral head thereby forming outer corners of the cylindrically formed head; i.) mounting a tower guide on said saw cutoff guide; j.) using a cylindrical drill, bore a starter hole for the stem of the metallic replacement femoral prostheses; k.) using a tapered drill matching the shape of the femoral prosthesis stem and said starter hole, bore a tapered hole to a measured depth into the head and neck of the femur; l.) inserting a tapered guide pin into the tapered hole; m.) using the tapered guide pin for alignment, chamfer the outer corners of the cylindrically formed femoral head thereby completing the formation of the exposed modified surface of the femoral head; n.) mounting a guide gauge on said tapered guide pin and checking for a uniform small clearance for cement all the way around the modified surface of said femoral head; and o.) applying cement to the exposed modified surface of said femoral head and within the femoral prosthesis, and mounting the femoral prosthesis on the femoral head and removing excess cement following seating of the femoral prosthesis; whereby an even layer of cement is located between said femoral prosthesis and the outer surface of said femoral head, when the tapered stem of said prosthesis is fitted down into said tapered hole, and said cement seals the lower edge of said prosthesis around the modified head and the adjacent neck of the femur.