Femoral Hip Prosthesis With Positioning And Drill Guide Assembly

Abstract

A hip joint prosthesis of generally conventional configuration in that it includes an elongated tapered spindle curving slightly laterally at its major dimension end with the latter including a partial spherical head for universal engagement in a pelvis mounted socket provided therefor. The prosthesis departs from the conventional prosthesis or similar apparatus in that the spindle is provided with longitudinally spaced and transversely extending apertures and one side of the head is provided bores with laterally outwardly opening parallel bores. A combined jig and drill guide is also provided and includes a plurality of locating pins telescopingly receivable in the bores and sleeve portions supported in fixed relation relative to the locating pins aligned with the apertures when the guide has its locating pins disposed in the bores. The spindle is first driven into the medullary cavity and thereafter the guide is positioned alongside the femur with the locating pins received in the bores. Thereafter, a suitable drill may be inserted through and guided by the sleeve portions for drilling bores in the femur aligned with the apertures formed in the spindle disposed in the medullary cavity. After removal of the drill guide suitable threaded fasteners may be threaded through the bres formed in the femur and the apertures formed in the spindle of the prosthesis to thereby lock the spindle in fixed relation relative to the femur so as to eliminate relative movement between the prosthesis spindle and the femur.

Description

The femoral hip prosthesis of the instant invention has been designed primarily to provide a device affording for firm fixation of an intramedullary prosthesis stem or spindle. The basic principle of providing indexing means on the prosthesis, apertures in the spindle and a jig for accurately guiding a drill bit in alignment with the spindle apertures may be extended to other appliances which require intramedullary stems for fixation.

At the present time, firm fixation of an intramedullary stem can be accomplished only by the utilization of bone cement (which is still in the experimental stage) or by providing the stem with slots or large apertures extending therethrough in the hope that bone will grow through the slots or apertures and thereby firmly fix the intramedullary stem. However, sufficient growth of bone may or may not occur and the chances of such bone growth occurring are substantially eliminated unless the initial placement of the intramedullary stem is sufficiently firm to prevent shifting for a length of time sufficient to allow for the desired new bone growth.

It may therefore be seen that the incidents of firm fixation of an intramedullary stem at present is low with the result being that the patient experiences considerable pain due to the shifting of the intramedullary stem.

It is accordingly the main object of this invention to provide a femoral hip prosthesis and positioning jig and drill guide therefore enabling suitable fasteners, such as threaded screws, to be utilized in firmly fixing the intramedullary stem in position once the stem has been inserted in the femur.

Another object of this invention is to provide a prosthesis and positioning jig and drill guide therefore to be utilized in a manner such that immediate firm fixation of the intramedullary stem of the prosthesis may be realized by a post-operative patient.

A final object of this invention to be specifically enumerated herein is to provide a hip prosthesis and positioning jig and drill guide which will conform to conventional forms of manufacture, be of simple construction and easy to use so as to provide a device that will be economically feasible and time saving in installation.

These together with other objects and advantages which will become subsequently apparent reside in the details of construction and operation as more fully hereinafter described and claimed, reference being had to the accompanying drawings forming a part ereof, wherein like numerals refer to like parts throughout, and in which:

FIG. 1 is a side elevational view of the prosthesis with the stem thereof seated within the femur and before firm fixation of the stem by threaded fasteners to the femur;

FIG. 2 is a view similar to FIG. 1 but with the positioning jig and drill guide in position prior to drilling the bores in the femur;

FIG. 3 is an elevational view of the assemblage illustrated in FIG. 2 as seen from the left side thereof and with an associated drill and drill bit illustrated in phantom lines;

FIG. 4 is a perspective view of the positioning jig and drill guide;

FIG. 5 is a view similar to FIG. 2 but illustrating a modified form of the positioning jig and drill guide enabling the guide to be also utilized in initially guiding the anchoring screws into position;

FIG. 6 is an elevational view of the assemblage illustrated in FIG. 5 as seen from the left side thereof;

FIG. 7 is a perspective view of the modified form of jig and drill guide;

FIG. 8 is a fragmentary elevational view of the modified form of jig and drill guide illustrating the manner in which the relatively pivotable portions thereof may be locked in the closed position;

FIG. 9 is a fragmentary elevational view illustrating the upper portion of the femur with one of the anchoring screws in position anchoring the stem of the prosthesis in position; and

FIG. 10 is a fragmentary sectional view taken substantially upon the plane indicated by the section line 10--10 of FIG. 9.

Referring now more specifically to the drawings, the numeral 10 generally designates the improved prosthesis of the instant invention including a longitudinally bowed and tapered stem 12 provided with longitudinally spaced and transversely extending apertures 14 which may or may not be threaded. The major dimension end of the stem 12 includes a bulbous or partial spherical head 16 and one side of the head 16 is provided with a plurality of parallel indexing bores 18.

With attention now invited more specifically to FIG. 4 of the drawings, there may be seen an indexing or positioning jig and drill guide referred to in general by the reference numeral 20. The guide 20 includes a generally planar body plate 22 which is elongated and longitudinally bowed. One end of the body plate has a plurality of positioning or indexing pins 24 secured therethrough and the pins 24 have their mid-portions secured through the body plate 22 so as to include two sets of corresponding ends disposed on the opposite sides of the plate 22. In addition, three longitudinally slotted drill guide sleeves 26 are secured through the body plate 22 at points spaced longitudinally therealong. The sleeves 26 also have their mid-portions secured through the body plate 22 in order that corresponding sets of ends of the sleeves 26 are disposed on opposite sides of the body plate 22. In operation, after the stem 12 of the prosthesis 10 has been seated within the femur 28 in the manner illustrated in FIG. 1 of the drawings, the guide 20 is disposed alongside the upper end of the femur 28 and the head 16 and laterally shifted so as to insert one pair of corresponding ends of the pins 24 in the bores 18. When thus positioned, the sleeves 26 are aligned with the apertures 24 and a drill bit 30 such as that illustrated in FIG. 3 of the drawings supported from a drill truck 32 may be successively guidingly received in the sleeves 26 in order to drill bores in the femur 28 precisely aligned with the apertures 14 formed in the stem 12. The bore may be formed in only one side of the femur or they may be formed completely through the femur as the bores 34 illustrated in FIG. 10 of the drawings. Thereafter, the guide 20 is removed and suitable threaded fasteners such as the fasteners 36 in FIGS. 9 and 10 may be utilized to firmly fix the stem 12 of the prosthesis within the femur 28.

With attention now invited more specifically to FIGS. 5-8 of the drawings, there may be seen a modified form of guide referred to in general by the reference numeral 40. The guide 40 includes a base plate 42 corresponding to the base plate 22 and positioning or indexing pins 44 corresponding to the pins 24. In addition, one edge portion of the base plate 40 includes semicylindrical drill guide sleeves 46 corresponding to the guide sleeves 26.

The guide 40, however, includes a secondary body plate 42' pivotally supported from the body plate 42 as at 43 and one edge portion of the plate 42' includes semi-cylindrical guide sleeves 46' which, when the free end portion of the plate 42' is swung toward the free end of the plate 42, coact with the semicylindrical guide 46 to form cylindrical guide sleeves.

The free end of the plate 42 includes a stiff but somewhat resilient hook portion 48 comprising a snap latch for engagement with the endmost semi-cylindrical guide sleeve 46 on the plate 42 in order to retain the plate 42' in the closed position thereof illustrated in FIG. 5 of the drawings.

The operation of the guide 40 is quite similar to the operation of the guide 20 in that the pins 44 are telescoped into the bores 18 whereupon the coacting semi-cylindrical guide sleeves 46' are aligned with the apertures 14 formed in the stem 12 of the prosthesis 10. Thereafter, the drill bit 30 and truck 32 supported from the drill may be utilized to form bores corresponding to the bores 34. Thereafter, and with the guide 40 still in position, fasteners 50 corresponding to the fasteners 36 may be passed between the pairs of coacting semi-cylindrical guide sleeves 46 and 46' and threaded in the bores formed in the femur 28 until the heads of the fasteners 50 are positioned closely adjacent the outer ends of the semi-cylindrical drill guide sleeves 46 and 46'. In this manner, the fasteners 50 are properly guided as they are threaded into the femur 28 and the stem 12 of the prosthesis 10. After all of the fasteners 50 have been at least initially threaded into the femur 28, the plate 42' may be swung to the open position thereof illustrated in FIG. 7 of the drawings to that the guide 40 may be removed from the prosthesis and femur prior to the fasteners 50 being fully seated. hereof,

The pins 24 and 44 project from opposite sides of the plates 22 and 42 in order that the guides 20 and 40 may be used on either side of the femur 28, according to the desire of the surgeon. Of course, either or both sides of the head 16 may be provided with bores 18 or the latter may comprise through bores as long as the pattern thereof is regular.

Although the stem 12 might be anchored in position by the utilization of fasteners 50 without the use of either the guide 20 or the guide 40, in order to insure absolute alignment of the bores formed in the femur 28 and the apertures 14 formed in the stem 12, the bores 34 and apertures 14 would have to be simultaneously formed and while bone dust caused by such a drilling operation would not necessarily be excessively objectionable, metal filings and chips as a result of the apertures 14 being formed in the stem 12 in situ would be highly objectionable and thus simultaneous forming of the bores 34 and apertures 14 in situ is intolerable. Furthermore, the guide 40 not only provides a means whereby the bores 34 may be formed in precise alignment with the preformed apertures 14, but also enables the fasteners 50 to be guided during initial engagement thereof with the femur 28.

While the spindle and jig of the invention are illustrated and described herein as being specifically adapted for use in affording firm fixation of an intramedullary prosthesis stem or spindle, the invention may also be practiced in affording firm fixation of any intramedullary nail or the like as long as one end portion of the nail is exposed and provided with indexing means of some type for coaction with complementary indexing means on a corresponding jig end.

The foregoing is considered as illustrative only of the principles of the invention. Further, since numerous modifications and changes will readily occur to those skilled in the art, it is not desired to limit the invention to the exact construction and operation shown and described, and accordingly all suitable modifications and equivalents may be resorted to, falling within the scope of the invention.

Claims

What is claimed as new is as follows:

1. In combination, a prosthesis comprising an elongated spindle having a head on one end and being adapted at its other end for endwise insertion into the exposed end of a bone component, said spindle being provided with longitudinally spaced transverse apertures, a positioning jig and drill guide assembly, said assembly including an elongated body, said head and one end of said body including coacting releasably engaged indexing means supporting said body from said head against longitudinal as well as transverse shifting and angular displacement relative to said prosthesis and with the other end portion of said body extending along said spindle, said other end portion of said body including means defining longitudinally spaced transversely extending guide means aligned with said apertures, said guide means being adapted to guidingly support a rotatable drill bit axially advanced toward said bone component with said drill bit aligned with said apertures, thereby insuring that the apertures or bores formed in the bone will be aligned with the apertures formed in the prosthesis spindle, said guide means comprising generally semi-cylindrical sleeve portions carried by and opening laterally outwardly of one marginal edge portion of said body, a secondary plate pivotally supported from said body for swinging movement of one edge portion thereof toward and away from the aforementioned edge portion of said body, the second mentioned edge portion including generally semi-cylindrical sleeve portions registrable with the first mentioned semi-cylindrical sleeve portions upon swinging of said edge portions together to form generally cylindrical sleeve portions through which said drill bit may be guidingly advanced.

2. The combination of claim 1 wherein said body member and the pivoted portion thereof include coacting means for releasably retaining said body and swingable portion against angular displacement relative to each other with said edge portions swung toward each other and said semi-cylindrical sleeve portions opposing each other to form cylindrical sleeves.