Method and apparatus for preparing a femur to receive a modular prosthetic femoral component

• US 6,517,581 B2
• Filed: 01/25/2001
• Issued: 02/11/2003
• Est. Priority Date: 01/25/2001
• Status: Expired due to Term

• Current Assignee: Zimmer Technology Incorporated (Zimmer Biomet Holdings, Inc.)
• Original Assignee: Zimmer Incorporated (Zimmer Biomet Holdings, Inc.)
• Inventors: Blamey, Jonathan
• Primary Examiner(s): Smith, Jeffrey A.
• Application Number:
  US09/770,009
• Publication Number:
  US 20020133233A1
• Time in Patent Office: 747 Days
• Field of Search: 606/79, 606/80, 606/85, 606/84, 606/172, 606/180, 303/52, 451/48, 623/22.12
• US Class Current: 623/22.12
• CPC Class Codes: A61B 17/164 intramedullary
• CPC Class Codes: A61B 17/1668 for the upper femur A61B17/164 takes precedence

Abstract

The present invention provides an improved method and apparatus for preparing a femur to receive a modular prosthetic femoral component. A distal reamer having a plurality of sets of depth marks is utilized to prepare the distal femoral canal. The sets of depth marks on the distal reamer correspond in number to the number of distal femoral stems available for use with the particular modular prosthetic femoral implant set. Each set of depth marks comprises a plurality of indicator rings corresponding in number to the number of proximal bodies adapted for utilization with the prosthetic femoral component set. Prior to distal reaming, the appropriate set of depth marks and indicator ring is chosen corresponding to the modular components the surgeon wishes to utilize. Reaming then takes place until the chosen indicator ring is aligned with a reference point (e.g., the top of the greater trochanter). Upon reaching the appropriate reaming depth, the distal reamer is left in place in the femoral canal. A cannulated forming tool, e.g. a rasp or reamer, is thereafter positioned over the shank of the distal reamer and utilized to effect proximal canal sizing. The distal reamer head is sized whereby the proximal reamer, e.g., will abut the reaming head of the distal reamer when the proximal reamer reaches the appropriate depth associated with the shortest distal stem of the modular femoral component set. In this way, the head of the distal reamer provides a mechanical stop for the proximal reamer so that both under reaming and over reaming are avoided. In cases in which a longer femoral stem is utilized, a cylindrical spacer having a length corresponding to the length difference between the shortest distal stem and the chosen distal stem is utilized to provide a mechanical stop for the proximal reamer. The reamer spacer includes an elongate aperture sized whereby the reamer spacer fits about the shank of the distal reamer.

Claims

1. An apparatus for preparing a femur to receive a modular prosthetic femoral implant, comprising:

a distal reamer having a distal reaming head and a shank, wherein said distal reamer includes a plurality of sets of depth marks, each said set of depth marks being indicative of a reaming depth corresponding to one of a plurality of distal stems forming a part of a modular prosthetic femoral implant set;

a cannulated forming tool sized to fit about said shank; and

a mechanical stop for limiting the travel of said cannulated forming tool when said cannulated forming tool is placed about said shank.

2. The apparatus of claim 1, wherein the cannulated forming tool comprises a cannulated reamer.

3. The apparatus of claim 2, wherein said distal reaming head comprises said mechanical stop.

4. The apparatus of claim 2, further comprising:

a reamer spacer sized to fit about said shank, said reamer spacer comprising said mechanical stop, said reamer spacer placed about said shank.

5. The apparatus of claim 2, wherein said cannulated reamer includes a proximal reaming head, said proximal reaming head operable to ream a proximal channel of a larger size than a distal channel reamed by said distal reaming head.

6. The apparatus of claim 1, wherein each of said set of depth marks comprises a plurality of indicator marks, each of said indicator marks being indicative of a reaming depth corresponding to one of a plurality of proximal bodies forming a part of said modular prosthetic femoral implant set.

7. The apparatus of claim 6, wherein each of said indicator marks comprises an indicator ring surrounding said shank of said distal reamer.

8. In combination, a modular prosthetic femoral implant set for replacing a portion of a femur and an apparatus for preparing the femur to receive a modular prosthetic femoral implant formed from said implant set, comprising:

a distal femoral stem for affixation to the femur, said distal femoral stem being seated in a femoral canal;

a distal reamer for reaming said femoral canal to receive said distal femoral stem, said distal reamer having a distal reaming head and a shank, wherein said distal reamer includes a plurality of sets of depth marks, each said set of depth marks being indicative of a reaming depth corresponding to one of a plurality of distal femoral stems forming a part of the modular prosthetic femoral implant set, said distal femoral stem being chosen from said plurality of distal femoral stems;

a cannulated reamer sized to fit about said shank, said cannulated reamer having a proximal reaming head sized to ream a proximal portion of said femoral canal, whereby said distal femoral stem will pass through said proximal portion of said femoral canal without interference; and

a mechanical stop for limiting the travel of said cannulated reamer when said cannulated reamer is placed about said shank of said distal reamer, whereby said mechanical stop prevents said cannulated reamer from reaming into an area of the femoral canal into which the distal femoral stem will be seated.

9. The combination of claim 8, wherein said distal reaming head comprises said mechanical stop.

10. The combination of claim 8, further comprising a reamer spacer sized to fit about said shank, said reamer spacer placed about said shank, said reamer spacer comprising said mechanical stop.

11. The combination of claim 8, further comprising a proximal femoral component for affixation to said distal femoral stem.

12. The combination of claim 8, wherein each of said set of depth marks comprises a plurality of indicator rings, each of said indicator rings being indicative of a reaming depth corresponding to one of a plurality of proximal bodies forming a part of the modular prosthetic femoral implant set.

13. A method of preparing a femur to receive a modular prosthetic implant, comprising:

providing a distal reamer having a mechanical stop associated therewith, said distal reamer further comprising a distal reaming head, a shank, and a plurality of sets of depth marks, each said set of depth marks being indicative of a reaming depth corresponding to one of a plurality of distal stems forming a part of a modular prosthetic femoral implant set;

choosing a distal femoral stem;

choosing one of said sets of depth marks corresponding to said distal femoral stem;

reaming the femur with said distal reamer to a depth wherein the chosen set of depth marks is aligned with a reference point;

providing a cannulated sizing tool sized to fit about the shank of said distal reamer;

with the distal reamer left in the femur, placing the cannulated sizing tool about said shank; and

advancing the cannulated sizing tool to form a proximal femoral canal in the femur, whereby said mechanical stop limits the travel of said cannulated sizing tool.

14. The method of claim 13, wherein the step of providing a cannulated sizing tool comprises providing a cannulated reamer, and the step of placing the cannulated sizing tool about said shank comprises placing the cannulated reamer about said shank, and the step of advancing the cannulated sizing tool to form a proximal femoral canal in the femur comprises reaming the femur with said cannulated reamer.

15. The method of claim 14, wherein said distal reaming head comprises said mechanical stop.

16. The method of claim 14, further comprising the steps of:

providing a reamer spacer sized to fit about the shank of said distal reamer; and

placing said reamer spacer about said shank before placing said cannulated reamer about said shank, whereby said reamer spacer comprises said mechanical stop.

19. The method of claim 13 or 17, wherein said reference point comprises the tip of the greater trochanter of the femur.

17. A method of preparing a femur to receive a modular prosthetic implant, comprising:

providing a distal reamer, wherein said distal reamer includes a plurality of sets of depth marks, each said set of depth marks being indicative of a reaming depth corresponding to one of a plurality of distal femoral stems forming a part of a modular prosthetic femoral implant set, each said set of depth marks comprising a plurality of indicator marks, each of said indicator marks being indicative of a reaming depth corresponding to one of a plurality of proximal bodies forming a part of the modular prosthetic implant set, said method further comprising;

choosing a distal femoral stem;

choosing a proximal body for affixation to said distal femoral stem;

choosing one of said sets of depth marks corresponding to said distal femoral stem;

choosing one of said indicator marks forming a part of said chosen set of depth marks said chosen indicator mark corresponding to said proximal body; and

wherein said step of reaming the femur with said distal reamer comprises reaming the femur with said distal reamer to a depth wherein the chosen indicator mark is aligned with a reference point.

18. The method of claim 17, further comprising:

seating the chosen distal femoral stem in the femoral canal formed by said reaming steps; and

affixing the chosen proximal body to said distal femoral stem.