Arthroplasty system and related methods

Patent metadata

Field	Value
Publication number	US-2017209221-A1
Application number	US-201715483560-A
Country	US
Kind code	A1
Filing date	Apr 10, 2017
Priority date	Dec 18, 2007
Publication date	Jul 27, 2017
Grant date	—

Abstract

A method of manufacturing an arthroplasty jig is disclosed herein. The method may include the following: generate a bone model, wherein the bone model includes a three dimensional computer model of at least a portion of a joint surface of a bone of a patient joint to undergo an arthroplasty procedure; generate an implant model, wherein the implant model includes a three dimensional computer model of at least a portion of a joint surface of an arthroplasty implant to be used in the arthroplasty procedure; assess a characteristic associated with the patient joint; generate a modified joint surface of the implant model by modifying at least a portion of a joint surface of the implant model according to the characteristic; and shape match the modified joint surface of the implant model and a corresponding joint surface of the bone model.

First claim

What is claimed is:

1 . A method of planning an arthroplasty of a knee joint, the method comprising:
computer define from image data of a first bone of the knee joint a sagittal elliptical contour of a condyle of the first bone of the knee joint, computer define from image data of an implant a sagittal elliptical contour of a condyle of the implant; computer align the defined elliptical contour of the condyle of the first bone with the defined elliptical contour of the condyle of the implant; subsequent to the elliptical contours being aligned, begin computer shape matching a condyle surface of the image data of the implant with a condyle surface of the image data of the first bone; and subsequent to the shape matching, computer define a resection of the first bone.

2 . The method of claim 1 , wherein defining the sagittal elliptical contour of the condyle of the first bone includes computer defining a tangent contact point representing a posterior extremity of the condyle of the first bone.

3 . The method of claim 2 , wherein defining the tangent contact point includes defining at least one of a plane or line that tangentially contacts the posterior extremity of the condyle of the first bone and is parallel to at least one of a line or plane extending along an anterior shaft of the first bone.

4 . The method of claim 3 , wherein the tangent contact point is on a major axis of the sagittal elliptical contour.

5 . The method of claim 1 , wherein defining the sagittal elliptical contour of the condyle of the first bone includes computer defining a tangent contact point representing a distal extremity of the condyle of the first bone.

6 . The method of claim 5 , wherein defining the tangent contact point includes defining at least one of a plane or line that tangentially contacts the distal extremity of the condyle of the first bone and is perpendicular to at least one of a line or plane extending along a shaft of the first bone and through a medial-lateral center of the shaft.

7 . The method of claim 6 , wherein the tangent contact point is on a minor axis of the sagittal elliptical contour.

8 . The method of claim 1 , wherein the shape matching employs a three-dimensional transformation.

9 . The method of claim 8 , wherein the three-dimensional transformation satisfies a least squares fit three-dimensional surface matching.

10 . The method of claim 1 , further comprising computer referencing with respect to location and orientation in a three dimensional computer coordinate system the defined resection with a registration surface of the first bone, the registration surface being defined from the image data of the first bone.

11 . A method of manufacturing a custom arthroplasty jig comprising the method of claim 10 and further comprising manufacturing the custom arthroplasty jig to have a resection guide and a custom mating surface defined according to the resection and the registration surface, respectively.

12 . A method of performing the arthroplasty of the knee joint comprising the method of claim 10 and further comprising contacting the first bone of the knee joint at a location corresponding to the registration surface and resecting the bone according to the defined resection, the contacting registering the defined resection with the first bone.

13 . The method of claim 12 , wherein the contacting is via a custom mating surface of a custom arthroplasty jig having a resection guide and the custom mating surface, the resection guide defined according to the resection and the custom mating surface defined according to the registration surface.

14 . The method of claim 1 , wherein the computer defining the resection of the first bone allows the implant, when implanted on the first bone, to achieve a post-surgical alignment of the knee joint that is a natural alignment of the knee joint that hypothetically existed prior to the knee joint assuming a degenerated state.

15 . The method of claim 1 , wherein the computer defining the resection of the first bone allows the implant, when implanted on the first bone, to achieve a post-surgical alignment of the knee joint that is a zero degree mechanical axis alignment of the knee joint.

16 . The method of claim 1 , wherein the image data includes image contour lines determined from MRI or CT images taken of the first bone.

17 . The method of claim 1 , wherein the image data includes at least one of two-dimensional contour lines or a three-dimensional computer model.

18 . The method of claim 1 , wherein the computer defining the resection of the first bone includes adjusting for cartilage thickness subsequent to the shape matching.

19 . The method of claim 18 , wherein the cartilage thickness adjustment is based on cartilage measurements taken of healthy cartilage in the knee joint.

20 . The method of claim 18 , wherein the cartilage thickness adjustment is based on a joint gap analysis of the knee joint.

Assignees

• Howmedica Osteonics Corp

Inventors

• Park Ilwhan
• Chi Charlie W
• Howell Stephen M

Classifications

• A61B17/1703

  using imaging means, e.g. by X-rays · CPC title

• A61B17/1725

  for applying transverse screws or pins through intramedullary nails or pins · CPC title

• G06T7/0012

  Biomedical image inspection · CPC title

• A61B17/1764

  for the knee · CPC title

• A61B5/4585

  Evaluating the knee · CPC title