Mill and guide apparatus for preparation of a hip prosthesis

Abstract

A guide apparatus for preparing the femur of a patient with a rotary mill to receive a femoral hip prosthesis includes a V-shaped guide body having a lower end base portion adapted to extend into the intermedullary canal of the femur and an upper end portion comprised of at least two spaced apart struts so that the overall guide body had a configuration substantially the same as the prosthesis body sought to be implanted in the patient. The lower end of the guide body base provides one or more hemispherical receptacles for holding the hemispherical end portion of a spinning mill bit. A preferably removable transverse guide rail has connection pins at one end portion thereof for forming a connection with the upper end of the guide body at one of the struts, the arm having a curved surface that is adapted to guide the mill bit during preparation of the intermedullary canal of the patient's femur for receiving a hip prosthesis thereafter.

Description

BACKGROUND OF THE INVENTION1. Field of the InventionThe present invention relates to a modular hip prosthesis system wherein various custom, selected component parts of an implant can be selected during the surgical procedure and a corresponding mill or rotary reamer guide selected to prepare the femur so that the implant can be custom fitted to a patient.2. General BackgroundIncreasingly, surgeons want to be able to custom fit femoral prostheses to patients. Instead of having to choose a properly sized prosthesis from a group of pre-formed implants, it would be advantageous to have a basic design which can be modified with various component parts. This would eliminate the need to maintain a large inventory and would provide better fitting implants. In addition, the femur of each patient can differ slightly so that some cutting and / or reaming of the intermedullary cavity is desireable for properly preparing the femur to receive the selected prosthesis.Custom fitted implants are part...

AI Technical Summary

Benefits of technology

The guide body preferably defines an envelope having a size and shape that corresponds to the shape of the upper end portion of the prosthesis body so that the guide body and the cut made by the reamer closely corresponds to the actual shape of the prosthesis to be implanted, thus eliminating the problem of a poor fit.

Problems solved by technology

Unpredictable, proximal and / or distal bone loss of deformity often occurs which must be accommodated by the replacement prosthesis.

Variations in intramedullary canal diameter can also occur, which if not accompanied by a properly sized implant, can result in distal toggle.

In short, it is difficult, of not impossible, to predict the exact shape of a hip implant which is suitable for all patients.

Since it is impractical and would be prohibitively expensive to maintain an inventory of implants for most patients, compromises must sometimes be made in supplying implants which fit reasonably well but could be improved upon.

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