Drill Jig For A Femoral Prosthesis

Abstract

A jig for forming one or more holes in the femur for the purpose of accommodating securement means utilized to anchor a prostheses forming a part of a hip joint to the femur. The jig includes an insert which is shaped like the shank of the femoral prosthesis and which is fitted into and seated in the femur in substantially the same manner as the prosthesis. This insert of the jig contains one or more guide bores for a work tool which forms one or more holes in the femoral bone for the purpose of accommodating the securement means utilized to anchor the prosthesis to the femur.

Description

SUMMARY OF THE INVENTION

This invention relates to a jig for forming one or more holes in the femur to accommodate securement means utilized to anchor a prosthesis constituting a part of the hip joint to the femur.

The jig of this invention includes an insert means which seats in the femur of a patient in substantially the same way as the femoral prosthesis will be seated in the femur. A tool guide part is spacedly connected to the insert means of the jig so as to be positioned outwardly of the femur when the insert means is seated in the femur. The insert means and tool guide part have one or more aligned guide bores for the purpose of accommodating a work tool which forms one or more holes in the femoral bone. The prosthesis includes a shank having one or more holes therein for receiving securement means, such as screws or pins, to anchor the prosthesis within the femur. The guide bores in the jig insert means are so positioned that the holes formed in the femoral bone by use of the jig will be aligned with the securement holes in the prosthesis as it seats in the femur.

Accordingly, it is an object of this invention to provide a jig forming one or more holes in the femur of a patient to accommodate securement members for the purpose of anchoring a hip joint prosthesis to the patient's femur.

Another object of this invention is to provide a drill jig for a femoral prostehsis.

Still another object of this invention is to provide a jig for forming holes in the femur of a patient which accommodate securement means used to accurately position a prostehsis within the femur.

Still another object of this invention is to provide a jig which is for a femoral prosthesis and which is of simple and expedient operation.

Other objects of this invention will become apparent upon a reading of the invention's description.

BRIEF DESCRIPTION OF THE DRAWINGS

A preferred embodiment of this invention has been chosen for purposes of illustration and description wherein:

FIG. 1 is a perspective view of a femoral prosthesis and the jig of this invention.

FIG. 2 is a perspective view of a femur having the jig of FIG. 1 operatively fitted to the femur.

FIG. 3 is a top plan view of the jig as seen along line 3--3 of FIG. 2.

FIG. 4 is a side view of the jig as seen along line 4--4 of FIG. 3.

FIG. 5 is a fragmentary sectional view taken along line 5--5 of FIG. 4.

FIG. 6 is a sectional view of the femur as shown in FIG. 5 with the femoral prosthesis illustrated in FIG. 1 fitted within the femur and anchored thereto.

DESCRIPTION OF THE PREFERRED EMBODIMENT

The preferred embodiment illustrated is not intended to be exhaustive or to limit the invention to the precise form disclosed. It is chosen and described in order to best explain the principles of the invention and its application and practical use to thereby enable others skilled in the art to best utilize the invention.

The femoral prosthesis 10 illustrated in FIG. 1 forms a part of the patient's hip joint when operatively positioned within the femur and is representative of but one of several different designs for such an artificial hip joint member. In each of the various designs of the jip joint member there are two basic parts: a shank which is fitted into the shaft of the femur and a head which is connected to the shank and which is fitted into the patient's acetabulum which may also be artificial. Reference numeral 12 designates the shank of prosthesis 10. Shank 12 includes an enlarged portion or platform 15 to which a head 16 is connected. Prosthesis 10 is constructed so as to be fitted into the shaft 33 of the patient's femur 34 (see FIG. 6) which has had its head and, if necessary, a portion of its trochanter surgically removed. Prosthesis 10 includes a plurality of holes 18 which are formed in shank 12, preferably adjacent platform 15. Holes 18 are utilized to accommodate screws 35, pins or similar securement means which are secured to the femur 34 of the patient and which serve to anchor the prosthesis to the femur.

Jig 22, shown in perspective form to the left of prosthesis 10 in FIG. 1, includes an insert part 24 and a tool guide part 26 which is spaced from insert part 24 and connected thereto by means of a plate 28. Insert part 24 is of the same size and of the same configuration as the shank 12 of the prosthesis 10 for which the jig is to be used. In some constructions of the jig of this invention the insert part thereof will need only to be sized and configured like the upper portion of the shank of the prosthesis with the insert part terminating such as where indicated by broken line 30 in FIG. 1. Insert part 24 has a plurality of guide bore openings 18' formed therein at the same location and of the same number as securement means openings 18 in prosthesis 10.

Tool guide part 26 of jig 22 is spaced from insert part 24 and has a plurality of guide bores 32 formed therein which are equal in number to and in alignment with guide bores 18' in the insert part. The spacing between tool guide part 26 and insert part 24 is such that the insert part can be fitted into femur 34, as shown in FIGS. 2, 3 and 5, with the guide part 26 located adjacently outwardly of the femur.

In utilizing the prosthesis jig of this invention, the physician first separates the affected femur from the acetabulum of the patient. The head of the femur is surgically removed. The jig is then grasped by a handle 36 or a similar grip means which is connected to plate 28 and the shank 12' of insert part 24 is inserted longitudinally into the femoral shaft until the platform 15' of the shank 12' is seated in the femur at the same location and in the same orientation as the platform 15 of hip prosthesis 10 will assume when fixed to the femur. While it may be necessary for the physician to remove portions of the femoral bone when inserting shank 12' of jig 22 into the femur of the patient to get a desired fit, only just enough of the bone necessary to precisely accommodate the jig and later the prosthesis will be removed, thereby avoiding the necessity for weakening the femur and taking more operative time than is absolutely necessary to properly fit the prosthesis to the femur. A drill 36 (shown in broken lines in FIGS. 2 and 5) or a similar type work tool is inserted through each pair of aligned guide bores 18' and 32 in jig 22 so as to form openings 38 in the femur which may extend only partially or entirely through the femur, depending upon the discretion of the physician. Once openings 38 have been formed in femur 34, jig 22 is removed and prosthesis 10 fitted in the femur with its shank 12 positioned therein as shank 12' of the jig was positioned in the femur during the formation of holes 38. With prosthesis 10 so positioned within femur 34, holes 38 formed in the femur will be aligned with holes 18 in shank 12 of the prosthesis. Screws 35 or similar securement means are then inserted through the aligned holes 38 and holes 18 and turned into the bone of the femur so as to anchor the prosthesis to the femur.

It is to be understood that the invention is not to be limited to the details herein given but may be modified within the scope of the appended claims.

Claims

What I claim is:

1. A jig for preparing the femur to receive a hip prosthesis, said prosthesis having a shank which includes a platform formed at one end to which head means is connected, said shank having a hole therethrough, said jig comprising means removably insertable into the shaft of said femur, said insert means being substantially sized and shaped like the platform and at least a portion of the remainder of the shank of said prosthesis and having a tool guide bore therethrough, and including grip means for inserting said insert means into said femoral shaft so that said guide bore will be positioned in the femur at substantially the same location as said hole in the prosthesis when the prosthesis is fitted for use with its shank extending into said femoral shaft, a guide part spaced from said insert means and having a tool guide bore therethrough, means rigidly connecting said guide part to said insert means for operation as a unit and for spacing said guide part from said insert means so as to enable said guide part to be positioned outwardly of the femur when said insert means is positioned in said femoral shaft, said guide bore in the guide part and insert means being aligned to accommodate a work tool means for forming a securement means receiving a hole in said femur when said insert means is positioned in said femoral shaft, said securement means receiving hole being aligned with said hole in said prosthesis shank when said prosthesis is fitted for use with said shank extending into the femoral shaft.

2. The prosthesis jig of claim 1 wherein said jig insert means is sized and shaped like the shank of said prosthesis.