Femoral slideway and method

Patent metadata

Field	Value
Publication number	US-2016166394-A1
Application number	US-201615044564-A
Country	US
Kind code	A1
Filing date	Feb 16, 2016
Priority date	Mar 2, 1999
Publication date	Jun 16, 2016
Grant date	—

Abstract

A femoral slideway and femoral slideway/femur-size template combination is employed to create an installed knee prosthesis that creates a reduced amount of stress in the collateral ligaments relative to previous prosthesis. In one embodiment, the reduced stress is achieved by employing a femoral slideway/femur-size template combination which results in installation of a femoral slideway which has a smaller dorsal-ventral dimension than a corresponding dimension of the femur prior to resection.

First claim

1 .- 18 . (canceled)

19 . A method for implanting a femoral slideway on a femur, comprising:
locating a point on a lower extremity of a femur, said point being located at a pre-determined distance from a plane tangent to at least one dorsalmost point of lateral and medial condyles of the femur, the pre-determined distance defined by a template having a permanently specified distance between a bore on a support part and a contact surface on a flank of the template, the support part and flank defined as a single piece, the contact surface configured to engage at least one of the dorsalmost points of the lateral and medial condyles of the femur; drilling a hole at said point; and selecting a femoral slideway having a dimension defined by a distance between a peg extending from the slideway, the peg configured for insertion into a corresponding hole formed in the femur, and a plane tangent to a dorsal sliding surface furthest away from the peg; and wherein said pre-determined distance is larger than said dimension by an amount determined prior to the locating step.

20 . The method of claim 19 , wherein said pre-determined distance is about 5% to about 15% larger than said dimension of the femoral slideway.

21 . The method of claim 19 , wherein selecting further comprises selecting a femoral slideway from a group of slideways, all of the slideways in said group having substantially equal peg-to-sliding-surface dimensions as defined by a distance between the peg and the plane tangent to the dorsal sliding surface furthest away from the peg, wherein each slideway in said group has a different dorsal condyle-to-ventral condyle distance.

22 . The method of claim 19 , further comprising resecting bone material from the femur such that more bone material is removed from a dorsal side of the femur than will be replaced by the slideway to allow for a reduction of the distance between the peg and a center of a turning radius of the dorsal side of the slideway, as compared to the unresected femur, in order to reduce a load on ligaments attached to the femur.

23 . The method of claim 22 , wherein the resecting includes removing about 10% more bone material from the dorsal side of the femur than is replaced by the slideway, as measured between said hole and a dorsalmost surface of the femur.

24 . A method for implanting a femoral slideway on a femur, comprising:
locating a point on a lower extremity of a femur, said point being located at a pre-determined distance from a plane tangent to at least one dorsalmost point of lateral and medial condyles of the femur, the pre-determined distance defined by a template having a permanently specified distance between a bore on a support part and a contact surface on a flank of the template, the support part and flank defined as a single piece, the contact surface configured to engage at least one of the dorsalmost points of the lateral and medial condyles of the femur; drilling a hole at said located point; resecting a predetermined amount of bone between the located point and the plane tangent to the at least one dorsalmost point; and selecting a femoral slideway having a peg extending from the slideway and at least one condyle shell, the peg configured for insertion into a corresponding hole formed in the femur, said condyle shell having a thickness less than the predetermined amount of resected bone.

25 . The method of claim 24 , wherein the condyle shell comprises a dorsal sliding surface and a posterior fitting surface, the thickness of the condyle being defined between said surfaces.

26 . The method of claim 24 , wherein selecting further comprises selecting a femoral slideway from a group of slideways, all of the slideways in said group having substantially equal peg-to-sliding-surface dimensions as defined by a distance between the peg and a plane tangent to a dorsal sliding surface of the condyle shell furthest away from the peg, wherein each slideway in said group has a different dorsal condyle-to-ventral condyle distance.

27 . The method of claim 24 , wherein the thickness of the condyle shell is also predetermined.

28 . The method of claim 24 , wherein the resecting allows for a reduction of the distance between the peg and a center of a turning radius of the dorsal side of the slideway, as compared to the unresected femur, in order to reduce a load on ligaments attached to the femur.

29 . The method of claim 24 , wherein the resecting includes removing about 10% more bone material from the dorsal side of the femur than is replaced by the femoral slideway, as measured between said hole and a dorsalmost surface of the femur.

30 . The method of claim 24 , wherein the femoral slideway comprises a plurality of femoral slideways of different sizes.

31 . The method of claim 19 , wherein said pre-determined distance is at least 5% larger than said dimension of the femoral slideway.

32 . The method of claim 31 , wherein said pre-determined distance is at least 10% larger than said dimension of the femoral slideway.

33 . The method of claim 19 , wherein said predetermined distance corresponds to the permanently specified distance of the template irrespective of the size of the femoral slideway.

34 . The method of claim 19 , wherein the femoral slideway comprises a plurality of femoral slideways of different sizes, and wherein said dimension is a constant distance for the plurality of femoral slideways.

Assignees

• Smith & Nephew Inc

Inventors

• Schmotzer Hans
• Schuler Peter
• Malzer Udo

Classifications

• A61F2002/30011

  differing in porosity · CPC title

• A61F2002/30616

  Sets comprising a plurality of prosthetic parts of different sizes or orientations · CPC title

• A61F2250/0024

  made from both porous and non-porous parts, e.g. adjacent parts · CPC title

• A61F2002/30324

  differing in thickness · CPC title

• A61F2310/00407

  Coating made of titanium or of Ti-based alloys · CPC title