System and method for performing arthroplasty of a joint and tracking a plumb line plane

1. A method of performing an arthroplasty of a stem-ball and socket joint with a surgical navigation system, the method comprising the steps of:

digitizing landmarks to provide geometrical parameters of the joint and a limb depending therefrom, including digitizing aspects of a socket region and the stem of the limb;

determining a range of motion parameter;

placing a force sensor in the joint;

collecting soft tissue tension force data from the force sensor while performing a range of motion analysis of the joint;

determining a soft tissue tension parameter from the soft tissue tension force data;

computing a functional goal based on landmark data, the range of motion parameter, the soft tissue tension parameter, and a database of potential implants;

solving for a socket orientation to minimize impingement taking into account stability constraints based on an identified center of rotation of the socket;

choosing an implant components combination and positioning to match the functional goal;

solving for a socket position to minimize impingement taking into account stability constraints based on an identified stem position and the identified center of rotation of the socket;

solving for a components combination and positioning to match the functional goal based on the socket position;

solving for a components combination and orientation to match the functional goal based on the socket position and the identified stem position;

choosing a final components combination and a final orientation of the components to match the functional goal;

preparing the joint to receive the final implant components; and

installing the final implant components into the joint.

2. The method of claim 1 , wherein a graph is displayed having axes showing positioning or sizing parameters of the components combination wherein a plurality of curves are displayed on the graph representing the effect of the geometrical parameters on anatomical, kinematical and tension values of the resulting joint configuration.

3. The method of claim 2 , wherein the graph has first and second axes wherein the first axis is an amount of anteversion and a second axis is an amount of inclination of the socket and wherein a plurality of curves are displayed on the graph showing the effect of the anteversion and inclination on anatomical, kinematical, and tension values of the resulting joint configuration.

4. The method of claim 2 , wherein the graph comprises first and second axes, wherein the first axis represents an amount of anteversion of the stem and the second axis represents an amount of neck angulation and socket offset, and wherein a plurality of curves is displayed on the graph showing the effect of the neck angulation and socket offset on anatomical, kinematical, and tension values of the resulting joint configuration.

5. The method of claim 2 , wherein a marker displays the first socket components position relative to the plurality of curves.

6. The method of claim 1 , wherein the joint is a hip joint.

7. The method of claim 1 , wherein the joint is a shoulder joint.

8. A method of performing an arthroplasty of a ball and socket joint with a surgical navigation system, the method comprising the steps of:

digitizing geometrical parameters and range of motion data of the joint, wherein the step of digitizing is performed with the surgical navigation system;

measuring soft tissue tension force data from a force sensor in a trial implant in the joint during movement of the limb about the joint and calculating a soft tissue tension parameter from the soft tissue tension force data;

selecting a first socket position that provides a selected stability and potential for impingement and based at least in part on the soft tissue tension parameter;

establishing an acceptable tolerance range from the first socket position with regard to limb length, distal/proximal displacement, and lateral/medial displacement;

selecting an initial implant combination of components;

calculating and graphically displaying on a display mechanism attributes of the initial implant combination of components and a position of the initial implant combination of components relative to a range of additional potential attributes for additional potential implant combinations of components and for additional positions of the initial combination of components;

modifying the initial implant combination of components and the initial position of the initial combination of components to arrive at a final implant combination of components and a final position of the final combination of components for selected functional properties of the joint while staying within the tolerance range; and

navigating the components to the final position with the aid of the surgical navigation system.

9. The method of claim 8 , wherein the step of digitizing is performed using a surgical instrument, wherein the position of the surgical instrument is tracked by the surgical navigation system during the step of digitizing.

10. The method of claim 8 , wherein a database of implant components is provided.

11. The method of claim 8 , wherein a graph is displayed having axes showing geometrical parameters of the implant combination of components wherein a plurality of curves are displayed on the graph representing the effect of the geometrical parameters on anatomical, kinematical and tension values of the resulting joint configuration.

12. The method of claim 11 , wherein the first axis is an amount of anteversion and a second axis is an amount of inclination of the socket and wherein a plurality of curves are displayed on the graph showing the effect of the anteversion and inclination of the socket on anatomical, kinematical and tension values of the resulting joint configuration.

13. The method of claim 11 , wherein the first axis is an amount of anteversion of the stem and a second axis is an amount of neck angulation and socket offset and wherein a plurality of curves are displayed on the graph showing the effect of the anteversion of the stem and the amount of neck angulation and socket offset on anatomical, kinematical and tension values of the resulting joint configuration.

14. The method of claim 11 , wherein a marker displays the first socket components position relative to the plurality of curves.

15. The method of claim 8 , wherein the joint is a hip joint.

16. The method of claim 8 , wherein the joint is a shoulder joint.

17. A method of performing an arthroplasty of a joint with a surgical navigation system, the method comprising the steps of:

establishing and tracking a functional plane of the joint relative to a predetermined at-rest position;

establishing and tracking a plumb line relative to the functional plane by leveling an operating table having one or more markers associated therewith for tracking the position of the operating table, linearly moving the leveled operating table between a first height position and a second height position, and tracking the position of at least one of the markers associated with the operating table at least at the first height position and the second height position;

preparing the joint to receive implant components;

choosing implant components that minimize impingement and maximize range of motion; and

inserting the chosen implant components into the prepared joint.

18. The method of claim 17 , wherein the functional plane is a frontal pelvic plane related to the stance of the pelvis while standing.

19. The method of claim 17 , wherein the joint is a ball and socket joint.

20. The method of claim 17 , wherein the joint is a hip joint.

21. The method of claim 17 , wherein the method further includes the steps of inserting trial components into the prepared joint; and evaluating the trial components relative to predetermined goals.