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

CROSS REFERENCE TO RELATED APPLICATIONS

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

FIGS. 1 and 8 show generally the preferred embodiment of the apparatus of the present invention designated generally by the numeral 10. Mill apparatus 10 includes a mill 11 having a base 12 portion at its lower end and a pair of spaced apart struts 13, 14 extending upwardly therefrom. The guide body 11 has a lower receptacle in the form of a pair of spaced apart hemispherical bearing cups 15, 16 each of which carries a corresponding hemispherical end portion 21 of reamer 20 (see FIGS. 1, 7, and 8) during use. The guide body has an overall shape and configuration, as shown in FIGS. 2 and 4, that corresponds to the shape of the upper end portion of a hip prosthesis to be implanted, so that the strut 13 defines a medial strut and the strut 14 defines a lateral strut.

The surgeon prepares the intermedullary canal with a broach, for example, which is generally shaped to the configuration of the prosthesis body to be implanted in the intermedullary canal. The broach (not shown) typically has an envelope that corresponds to the envelope of the prosthesis body to be implanted. After the surgeon prepares the intermedullary canal using the broach, the guide body 11 is inserted into the intermedullary canal and a particular guide rail 30 selected by the surgeon depending upon the shape of the desired cut to be made by the mill, and as selected by the surgeon. It is possible that cutting on one side of the guide body only would be desired, and thus the surgeon may only use the mill to cut on one side, as shown in FIG. 1.

The arm 31 would preferably be reversible in order to cut on both medial and lateral sides of the intermedullary canal. In that respect, the guide rail 30 would preferably be removable from the guide body 11, and reversible, having pairs of attachment pins 31, 32 on both its upper and its lower surfaces. Pin openings 17, 18 in guide body receive corresponding pins 31, 32 of guide rail to form the connection. In FIG. 1, the lower surface set of pins 31, 32 is not shown because the lower set of pins are in the openings 17, 18.

In the embodiment of FIGS. 9--13, a dove-tail connector 34 would be provided on each side of guide arm 30 for connecting with a corresponding dove-tailed groove 39 milled in the top of the strut 13, so that the guide rail 30 has the same generally horizontal orientation as with the preferred construction of FIG. 1. Thus, when connector 34 registers in groove 39, the rail 30 can be extended either rearwardly of guide body 11 for posterior cuts and forwardly of guide body 11 for anterior cuts. Stop pins 38 limit the movement of guide rail 30 with respect to body 11 during milling or cutting using mill.

Once attached, the guide rail 30 provides a generally curved guide surface 35 that extends between the connection end portion 40 of guide rail 30 to the free end 37 portion thereof. The shape of guide surface 35 would vary, depending upon the size of the cut to be made by the mill 20 as selected by the surgeon. Thus, a plurality of guide rails 30 could be provided in kit form to the surgeon, each with a different curvature or configuration of surface 35.

The surface 35 would be a abutted during operation with bearing sleeve 22 of mill 20, as shown in FIG. 1. The sleeve 22 could be removably attached to the central portion 23 of mill 20 which could be in the form of a reduced diameter section 25 of mill 20 as shown in FIG. 7.

The upper end portion 28 of mill 20 has a tool receptive tip having multiple flat surfaces 27 which are circumferentially spaced (see FIG. 6) so that a drill or the like could be attached to drive mill 20. A plurality of circumferentially spaced apart blades 24 would be provided on the lower end of mill 20 for the purposes of cutting away bone tissue during use.

Because many varying and different embodiments may be made within the scope of the inventive concept herein taught, and because many modifications may be made in the embodiments herein detailed in accordance with the descriptive requirement of the low, it is to be understood that the details herein are to be interpreted as illustrative and not in a limiting sense.

Claims

1. A guide apparatus for preparing the femur of a patient with a mill to receive a femoral hip prosthesis comprising:

a) a guide body having a lower end base, the guide body being connectable to adapted to extend into the intermedullary canal of the a patient's femur during use, and having an upper end portion comprised of at least one strut;

b) the lower end of the base having guide body including receptacle means for holding one end of a spinning mill;

c) a at least a partially curved transverse guide rail having connection means thereon for forming a connection with the upper end of the guide body, the rail having a at least a partially curved surface that is adapted to guide the mill during preparation of the intermedullary intramedullary canal of the patient's femur for receiving a hip prosthesis.

2. The apparatus of claim 1 wherein the guide body comprises a base with a pair of struts extending upwardly therefrom.

3. The apparatus of claim 2 further comprising a receptacle formed on the upper end portion of the guide body for receiving the connection means portion of the guide rail.

4. The apparatus of claim 1 wherein the connection forming means comprises a reversible connector that attached the guide rail to the guide body in multiple positions.

5. The apparatus of claim 1 wherein the guide body is V-shaped and includes medial and lateral spaced apart struts.

6. The apparatus of claim 5 wherein the connection means forms a connection with the medial strut.

7. The apparatus of claim 5 wherein the connection means comprises a receptacle carried by one of the struts of the V-shaped body, and a pair of opposed pegs carried by one end portion of the guide rail for respectively attaching the guide rail to the guide body and pre-selected left and right respective positions so that the guide rail can be used to form posterior and anterior sides of the intermedullary intramedullary canal.

8. The apparatus of claim 5 wherein the V-shaped guide body includes a pair of spaced apart struts including a generally vertically upstanding strut and inclined strut forming an acute angle therewith.

9. The apparatus of claim 5 wherein the guide body defines an envelope having a shape corresponding to the shape of an upper end portion of the prosthesis body to be placed in the patient's femur.

10. The apparatus of claim 1 wherein the receptacle means includes a pair of spaced apart, anterior and posterior receptacles each being sized to receive the lower end portion of the mill.

11. The apparatus of claim 1 wherein the guide body defines an envelope having substantially the same configuration as the prosthesis body sought to be implanted in the patient.

12. The apparatus of claim 1 wherein the guide rail includes a curved arm portion having a bearing surface thereon which allows the mill to track and an arcuate path extending generally away from the central axis of the intermedullary intramedullary canal so that the mill forms a cut in the intermedullary intramedullary canal that increases the size of the intermedullary intramedullary canal from the distal end portion thereof to the proximal end portion thereof.

13. The apparatus of claim 1 wherein the guide rail includes a cantilevered arm portion extending away from the connection means, the cantilevered arm carrying a curved guide surface that is positioned to engage the mid-section of the mill during use.

14. A guide apparatus for preparing the femur with a mill to receive a hip prosthesis comprising:

a) a V-shaped guide body having substantially the same configuration as a corresponding hip prosthesis to be implanted, said guide body including a lower end base configured to extend at least partially into the intermedullary intramedullary canal of the femur, and an upper end portion comprised of a pair of spaced apart struts forming a V-shaped configuration;

b) an elongated mill having a lower end portion with a hemispherical tip thereon and circumferentially spaced apart cutter blades extending between the hemispherical tip and at least a mid-section of the mill, and an upper end portion of the mill having a tooled end portion to receive a rotary drill for rotating the bit;

c) the lower end of the base having receptacle means for holding the end of a spinning mill bit;

d) a curved guide rail having connection means thereon for forming a connection with one of said struts, said guide rail having an arm extending substantially transverse to said struts, said arm having a curved surface that is adapted to guide the reamer bit during therealong as the hemispherical tip pivots in said receptacle means thereby preparing the intermedullary intramedullary canal for receipt of the hip prosthesis.

15. A guide apparatus for preparing the femur of a patient with a mill to receive a femoral hip prosthesis, comprising:

a) a guide body having an upper end portion and a lower end portion, the guide body being connectable to a patient's femur, forming a connection therewith during use;

b) the guide body including means for holding a spinning mill during a cutting of the patient's femur at the intramedullary canal of the femur;

c) an at least partially curved guide rail portion that extends generally transversely with respect to the mill, the rail having means for forming a connection with the upper end portion of the guide body, the rail having a surface that is adapted to guide the mill during preparation of the intramedullary canal of the patient's femur for receiving a hip prosthesis.

16. A method of for preparing the femur of a patient with a mill to receive a femoral hip prosthesis, comprising the steps of:

a) attaching a guide body having an upper end portion and a lower end portion to the patient's femur, forming a connection therewith;

b) supporting a spinning mill upon the guide body during a cutting of the patient's femur at the intramedullary canal of the patient's femur;

c) cutting the patient's bone tissue at the intramedullary canal using the spinning mill;

d) guiding transverse movement of the spinning mill during cutting of the patient's bone tissue at the intramedullary canal of the patient's femur with a guide rail portion that extends generally transversely with respect to the mill, the rail being connected during use to the guide body, the rail having a surface that is adapted to guide the mill during preparation of the intramedullary canal of the patient's femur for receiving a hip prosthesis.

17. The method of claim 16 wherein the rail is removably attachable to the guide body.

18. The method of claim 17 wherein in step "a" the lower end of the guide body is attached to the patient's femur.

19. The method of claim 16 wherein in step "b" the mill extends partially into the patient's femur during cutting thereof.

20. The method of claim 16 wherein the rail prevents excess cutting of bone tissue by the mill by limiting transverse movement of the mill.

21. The method of claim 16, wherein the mill is generally aligned with the central longitudinal axis of the patient's intramedullary canal.