Apparatus and method of ligament balancing and component fit check in total knee arthroplasty

• US 20030153978A1
• Filed: 02/08/2002
• Published: 08/14/2003
• Est. Priority Date: 02/08/2002
• Status: Abandoned Application

• Current Assignee: Whiteside Biomechanics, Inc.
• Original Assignee: Whiteside Biomechanics, Inc.
• Inventors: Whiteside, Leo A.
• Application Number:
  US10/072,372
• Publication Number:
  US 20030153978A1
• Time in Patent Office: Days
• US Class Current: 623/20.21
• CPC Class Codes: A61B 2017/564 Methods for bone or joint treatment
• CPC Class Codes: A61B 2034/102 Modelling of surgical devices, implants or prosthesis
• CPC Class Codes: A61B 2034/105 Modelling of the patient, e.g. for ligaments or bones
• CPC Class Codes: A61B 2034/2055 Optical tracking systems
• CPC Class Codes: A61B 2090/3983 Reference marker arrangements for use with image guided surgery
• CPC Class Codes: A61B 34/10 Computer-aided planning, simulation or modelling of surgical operations
• CPC Class Codes: A61B 34/20 Surgical navigation systems; Devices for tracking or guiding surgical instruments, e.g. for frameless stereotaxis
• CPC Class Codes: A61B 5/103 Detecting, measuring or recording devices for testing the shape, pattern, colour, size or movement of the body or parts thereof, for diagnostic purposes A61B5/08 takes precedence; measuring aids for tailors A41H1/00; measuring instruments specially adapted for dentistry A61C19/04
• CPC Class Codes: A61B 5/1127 using markers
• CPC Class Codes: A61B 5/4528 Joints A61B5/4533, A61B5/4538 take precedence
• CPC Class Codes: A61B 5/4533 Ligaments
• CPC Class Codes: A61B 90/36 Image-producing devices or illumination devices not otherwise provided for
• CPC Class Codes: A61B 90/361 Image-producing devices, e.g. surgical cameras
• CPC Class Codes: A61F 2/38 for elbows or knees
• CPC Class Codes: A61F 2/3859 Femoral components
• CPC Class Codes: A61F 2/389 Tibial components A61F2/3868 takes precedence
• CPC Class Codes: A61F 2/4657 Measuring instruments used for implanting artificial joints for surgical instruments A61B90/06
• CPC Class Codes: A61F 2/4684 Trial or dummy prostheses
• CPC Class Codes: A61F 2002/4632 using computer-controlled surgery, e.g. robotic surgery
• CPC Class Codes: A61F 2002/4666 for measuring force, pressure or mechanical tension
• CPC Class Codes: A61F 2002/4696 : optical

Abstract

Apparatus and method for determining the kinematics of a large joint (e.g., a knee) undergoing arthroplasty, for comparing the kinematics of the joint undergoing surgery with the kinematics of the normal joint, and for providing the surgeon with information allowing the balancing of the ligaments of the joint upon the installation of a prosthesis replacement joint. The apparatus includes optical targets mounted on joint replacement components fitted to the resected bones of the joint. One or more video cameras are used to obtain a series of images of the various optical targets as the extremity is flexed, extended, and rotated. A computer is responsive to the images of the targets to determine the kinematics of the joint as it is flexed, extended and rotated. The computer compares the kinematics of the observed joint with the kinematics of a normal joint and determines, based on anomalies of the observed joint relative to the normal joint, whether other implant components or spacers are required, and determines which ligaments must be relaxed or contracted so that the ligaments are balanced. The computer displays suggestions to the surgeon for changing components and for relaxing or contracting specific ligaments such that the ligaments of the joint is balanced with the prosthesis joint in place. A method of computer ligament balancing is also disclosed.

Claims

1. Apparatus for balancing the ligaments of a large joint during joint replacement surgery where a diseased joint is replaced with a prosthesis joint, for comparing the ligaments of the joint undergoing surgery with the ligaments of a normal joint, and for providing the surgeon with information allowing the balancing of the ligaments of the joint after the prosthesis joint has been installed, said apparatus comprising a plurality optical targets mounted on said prosthesis joint fitted to the resected bone surfaces of the joint, one or more video cameras obtaining a series of images of said optical targets as the joint is flexed, extended, and rotated, a computer responsive to the images of the targets to determine the kinematics of the prosthesis joint as it is flexed, extended and rotated, said computer comparing the kinematics of the prosthesis joint with the kinematics of a normal joint and determining, based on anomalies of the observed prosthesis joint relative to the normal joint, whether other prosthesis joint components or spacers are required in order for the prosthesis joint to operate properly and determining which ligaments of the joint must be relaxed or contracted so that the ligaments of the joint are balanced after installation of the prosthesis joint, said computer displaying suggestions to the surgeon for changing said prosthesis components and/or for adding or removing said spacers, and displaying suggestions for relaxing or contracting specific ligaments such that the ligaments of the joint are balanced with the replacement joint in place.

2. Apparatus as set forth in claim 1 wherein said computer determining whether other prosthesis components or spacers are required in order for the prosthesis joint to operate properly and said computer displaying suggestions to the surgeon for changing said prosthesis components or adding or removing spacers.

3. Apparatus as set forth in claim 1 wherein said large joint is a knee, and wherein said apparatus further comprises a trial femoral prosthesis component fitted to the resected surfaces of the femur and a trial tibial prosthesis component fitted to the resected surfaces of the tibia, said trial prosthesis components having said optical targets affixed thereto.

4. Apparatus for determining the kinematics of a large joint undergoing arthroplasty, for comparing the kinematics of the joint with trial prosthetic joint components fitted to resected bone surfaces of the joint with the kinematics of a normal joint, and for providing the surgeon with information allowing the balancing of the ligaments of the joint with a prosthesis joint in place, said apparatus including a plurality of optical targets mounted on said trial joint replacement components fitted to the resected bone surfaces of the joint, the position and orientation of each of said targets being known with respect to its respective said trial component such that by knowing the position and orientation of said targets of said respective trial components the position and orientation of said trial components is known, one or more video cameras, said one or more cameras being positioned with respect to said joint such that as the joint is flexed, extended and rotated by the surgeon said targets are within the field of view of said one or more cameras, said one or more cameras obtaining a series of images of the optical targets as the joint is flexed, extended, and rotated, a computer responsive to the images of the targets for determining the position and orientation of the targets and hence of the trial components with respect to said one or more cameras, said computer determining the position and orientation of said trial components with respect to one another as the knee is flexed, extended and rotated thereby enabling the determination of the kinematics of the joint, said computer comparing the kinematics of the observed joint with the kinematics of a normal joint and determining, based on anomalies of the observed joint relative to the normal joint, which ligaments must be relaxed or contracted so that with the prosthesis joint installed the ligaments are balanced, said computer displaying suggestions to the surgeon for relaxing or contracting specific ligaments so that the ligaments may be balanced.

5. Apparatus for determining the kinematics of prosthesis joint components relative to one another and relative to a normal joint during joint replacement surgery to aid the surgeon in fitting joint components to the resected bones of the joint undergoing surgery and to aid the surgeon in balancing the ligaments of the joint after a prosthesis joint has been installed, said apparatus comprising:

a. a first set of optical targets mounted to a first trial joint component fitted to a first resected bone of the joint, said first set of optical targets being in a predetermined geometrical relationship with respect to said first trial joint component;

b. a second set of optical targets mounted to a second trial joint component fitted to a second resected bone of the joint, said second set of optical targets being in a predetermined geometrical position with respect to said second trial joint component;

c. a video camera disposed to receive images of said first optical targets and said second optical targets, said video camera having a field of view, said first and second sets of targets being within said field of view as the joint is flexed, extended and rotated;

d. a computer operatively connected to said camera, said computer being responsive to the images of said first and second sets of targets to determine values of the position and orientation of said trial joint replacement components in space and with respect to one another and to determine the kinematics of the trial joint components relative to one another as the joint is extended, flexed and rotated; and

e. said computer displaying information to the surgeon relating to the balancing of the ligaments of the joint.

6. A method of balancing the ligaments of the knee during total knee arthroplasty comprising the steps of:

a. resecting the distal end of the femur so as to receive a femoral prosthesis implant;

b. resecting the proximal end of the tibia so as to receive a tibial prosthesis implant;

c. fitting trial implant components to the resected ends of the femur and tibia, said trial components having a plurality of optical targets affixed thereto with the location of the targets for each trial component being known;

d. manipulating the extremity in flexion, extension and rotation;

e. viewing said optical targets on said trial components with an video camera as said extremity is manipulated;

f. determining the position and orientation of the targets with respect to said camera;

g. determining the position and orientation of said trial components with respect to one another so that the kinematics of the trial components relative to one another may be determined;

h. identifying anomalies between the observed kinematics of the trial components as the extremity is manipulated which result from an unbalance of the ligaments of the knee; and

i. suggesting to the surgeon which of the ligaments of the knee should be adjusted either by relaxing or contracting such ligaments such that upon installation of the prosthesis components the ligaments of the knee are balanced.