Femoral cutting guide

• US 5,454,816 A
• Filed: 05/25/1994
• Issued: 10/03/1995
• Est. Priority Date: 02/07/1992
• Status: Expired due to Term

• Current Assignee: Howmedica International S. De R.L. (Stryker Corporation)
• Original Assignee: Howmedica International Incorporated
• Inventors: Ashby, Alan M.
• Primary Examiner(s): Pellegrino, Stephen C.
• Assistant Examiner(s): Tucker, Guy V.
• Application Number:
  US08/248,829
• Time in Patent Office: 496 Days
• Field of Search: 606/88, 606/87, 606/96, 606/102, 606/86, 606/82, 606/79, 606/80, 623/20
• US Class Current: 606/88
• CPC Class Codes: A61B 17/155 Cutting femur

Abstract

An orthopedic instrument for guiding a saw blade for preparing the distal end of a human femur to receive an endoprosthetic femoral component has a base component provided with guide for guiding cutting blades. The guide can be used to shape all of the necessary femoral surfaces to receive the femoral component to be fitted once the base component is fitted to the bone. A device for aligning the base component on the bone elements for attaching the base component to the bone after alignment is also provided.

Claims

1. A femoral cutting guide for guiding system a cutting device for preparing the distal end of a human femur to receive an endoprosthetic femoral component comprising:

a base component including a pair of side walls;

a plurality of spaced apart guide rods extending between said side walls for guiding the cutting device for forming a distal femoral surface, an anterior femoral surface, a posterior femoral surface, and anterior and posterior chamfered femoral surfaces for receiving a femoral component;

an accessory removably attachable to one of said rods;

means for aligning said base component on the bone, including an intramedullary rod and an element having a generally circular hole for allowing the insertion of the intramedullary rod therethrough, said element removably attachable to said accessory, said hole adapted to be positioned adjacent the intercondylar notch of the distal femur when said element is attached to said accessory and said accessory is attached to one of said rods; and

pin elements for attaching said base component to medial and lateral bone surfaces after alignment, said pin elements extending through holes in said side walls, said holes located proximally of said guide rods when said cutting guide is mounted on said femur.

2. The femoral cutting guide system as set forth in claim 1 further comprising an anterior anchor mounted on said base component to provide alignment said anterior anchor including means for anchoring said base component to the anterior cortex of the femur with which the instrument is to be used.

3. The femoral cutting guide system as set forth in claim 1 wherein said accessory is a posterior alignment accessory having a location means thereon which can locate against the posterior condyles of the bone and which acts as a condylar sled.

4. The femoral cutting guide system as set forth in claim 3 further including a sizing stylus wherein said posterior alignment accessory has means for attaching a sizing stylus.

5. The femoral cutting guide system as set forth in claim 4 wherein said sizing stylus and said posterior alignment accessory have cooperating indicators to indicate the appropriate femoral component size required.

6. The femoral cutting guide system as set forth in claim 3 including an extramedullary alignment guide removably attachable to said posterior alignment accessory and including means for orientating the guide system relative to the femoral geometry of the bone.

7. The femoral cutting guide system as set forth in claim 6 wherein said means for orientating is adapted to overlie the anterior surface of the femur to align to the femoral head from the center of the knee for varus-valgus alignment.

8. The femoral cutting guide system as set forth in claim 6 wherein said means for orientating provides extramedullary alignment by using the line of the anterior femoral shaft for varus-valgus orientation.

9. The femoral cutting guide system as set forth in claim 6 wherein a plurality of positions are provided for the orientating means.

10. The femoral cutting guide system as set forth in claim 6 wherein said extramedullary alignment guide incorporates means for guiding a drill for forming an entry hole in the intramedullary cavity to correspond with the intramedullary stem of a femoral implant component.

11. The femoral cutting guide system as set forth in claim 1 further comprising means to externally rotate a femoral component to be fitted relative to the natural anatomy of the femur and which includes means for rotating said base component relative to the bone.

12. The femoral cutting guides system as set forth in claim 1 wherein said guide rods are adapted to guide a saw blade.

13. A femoral cutting guide for guiding a saw blade for forming distal, posterior, anterior, anterior chamfer and posterior chamfer cuts on a distal femur to thus form a surface for mating with a prosthetic femoral component, the cutting guide comprising:

a pair of side plates;

a plurality of guide rods mounted to each side plate and extending therebetween to separate said plates, said guide rods mounted on said plates with respect to one another in a manner whereby five saw blade paths are defined, said distal cut in a direction transverse to a longitudinal axis of the femur, said anterior and posterior femoral cuts in directions parallel to said longitudinal axis and said anterior and posterior chamfer cuts at an angle to said longitudinal axis with at least one guide rod on each side of each cutting path, said guide rods of each side of said cutting paths spaced apart in a direction perpendicular to the cutting path a distance only slightly greater than a thickness of the saw blade so that said guide rods maintain the saw blades along said cutting path, means for aligning said base component on the bone, including an intramedullary rod and an element having a generally circular hole for allowing the insertion of the intramedullary rod therethrough said element attached to one of said guide rods, said generally circular hole adapted to be positioned adjacent the intercondylar notch of the distal femur; and

a pair of generally circular holes for receiving pins in each of said side plates for mounting one of said pair of side plates to a medial side of the distal femur and the other plate to the lateral side of the distal femur, said holes located proximally of said rods when said cutting guide is mounted on the femur and angled towards said intramedullary rod.

14. A cutting guide for guiding a saw blade during the preparation of a distal femur for the implant of a femoral knee prosthesis, said cutting guide enabling guiding of said saw blade for cutting a distal face cut in a direction transverse to a longitudinal axis of the femur, an anterior femoral cut in a direction parallel to said longitudinal axis, an posterior femoral cut in a direction parallel to said longitudinal axis, an anterior chamfer and a posterior chamfer cut in a direction at an angle to said longitudinal axis of the femur, while said cutting guide remains located and secured to the femur in a single position on the distal femur, said cutting guide comprising:

a pair of side plates;

a first set of guide members extending laterally between said side plates and located to delineate transversely opposite boundaries of an axially directed anterior cutting path intercepting the anterior femur, said first set of guide members including opposite guide surfaces spaced apart axially along said anterior cutting path for guiding said saw blade along said anterior cutting path during the anterior femoral cut;

a second set of guide members spaced from said first set of guide members, said second set of guide members extending laterally between said side members and located to delineate transversely opposite boundaries of an axially directed posterior cutting path intercepting the posterior femur, said second set of guide members including opposite guide surfaces spaced axially along said posterior cutting path for guiding said saw blade along said posterior cutting path during the posterior femoral cut;

a third set of guide members extending laterally between said side members located to delineate opposite boundaries of a transversely directed distal cutting path intersecting the distal femur, said third set of guide members including opposite guide surfaces spaced apart axially along said transverse distal cutting path during the distal femoral cut; and

a further set of guide members extending laterally between said side members and located for delineating transversely opposite boundaries of an oblique anterior chamfer cutting path and delineating transversely opposite boundaries of an oblique posterior chamfer cutting path, said further guide members including first opposite guide surfaces spaced apart along said oblique anterior chamfer cutting path for guiding said saw blade along said oblique anterior chamfer cut and second opposite guide surfaces spaced apart along said oblique posterior chamfer cutting path for guiding said saw blade during the posterior chamfer cut;

said side members being spaced apart laterally a distance sufficient to provide each of said delineated anterior cutting path, posterior cutting path, distal cutting path, anterior chamfer cutting path and posterior chamfer cutting path with a continuous, uninterrupted lateral extent corresponding to the full lateral extent of the respective transverse distal cut, anterior femoral cut, posterior femoral cut, anterior chamfer and posterior chamfer, whereby the full anterior femoral cut, the full posterior femoral cut, the full transverse distal cut, the full anterior chamfer and the full posterior chamfer cuts and accomplished while said cutting guide is located and secured on the femur in the single position;

means for aligning said base component on the bone, including an intramedullary rod and an element having a generally circular hole for allowing the insertion of the intramedullary rod therethrough mounted on one of said guide members, said hole adapted to be positioned adjacent the intercondylar notch of the distal femur; and

a pair of generally circular holes for receiving pins in each of said side plates for mounting one of said pair of side plates to a medial side of the distal femur and the other plate to the lateral side of the distal femur, said holes located proximally of said guide members when said cutting guide is mounted on the femur.