Knee evaluation and arthroplasty method

Abstract

A method of evaluating a human joint including bones and ligaments under anatomical tension to connect the bones. The method includes: defining a primary datum oriented and fixed in six degrees of freedom; defining at least one secondary datum having fixed origins relative to one of the bones of the joint and relative to a tracking device affixed to the bone; providing an electronic receiving device; while moving the bones of the joint relative to each other, using the electronic receiving device to collect data from the at least one tracking device, wherein the data includes information describing the position and movement in six degrees of freedom of the at least one secondary datum relative to the primary datum to produce a digital geometric model of at least a portion of the joint; and storing the digital geometric model for further use.

What is claimed is: 
     
         1 . A method of evaluating a human joint which includes two or more bones and ligaments, wherein the ligaments are under anatomical tension to connect the bones together, creating a load-bearing articulating joint, the method comprising:
 defining a primary datum oriented and fixed in six degrees of freedom;   defining at least one secondary datum, each secondary datum having fixed origins relative to one of the bones of the joint and relative to a tracking device affixed to the bone;   providing an electronic receiving device;   while moving the bones of the joint relative to each other, using the electronic receiving device to collect data from the at least one tracking device, wherein the data includes information describing the position and movement in six degrees of freedom of the at least one secondary datum relative to the primary datum, to produce a digital geometric model of at least a portion of the joint; and   storing the digital geometric model for further use.   
     
     
         2 . The method of  claim 1 , wherein:
 the joint is a knee joint which includes a femur bone, a tibia bone, and ligaments; and   the method further includes inserting into the joint a tensioner-balancer that includes a tibial interface surface, an opposed femoral interface surface, and a means of controlling distraction force.   
     
     
         3 . The method of  claim 2  further comprising using the tensioner-balancer to distract the knee joint. 
     
     
         4 . The method of  claim 3  further comprising using the information gathered to determine ligament physical characteristics that can be supplied as specific parameters for a software algorithm or machine learning system. 
     
     
         5 . The method of  claim 3 , wherein the tensioner-balancer includes a tibial interface surface, an opposed femoral interface surface, an array of tibial force sensors disposed on the tibial interface surface, and an array of femoral force sensors disposed on the femoral interface surface. 
     
     
         6 . The method of  claim 3  further comprising performing a tibial plateau cut before inserting the tensioner-balancer. 
     
     
         7 . The method of  claim 1  wherein the joint is a hip joint which includes a femur bone, a pelvic bone, and ligaments. 
     
     
         8 . The method of  claim 1 , wherein the joint is a shoulder joint which includes a humerus bone, a scapula bone, and ligaments. 
     
     
         9 . The method of  claim 1  wherein the primary datum is established by physically registering bony landmarks on at least one of the bones. 
     
     
         10 . The method of  claim 1  wherein: the joint is a knee joint which includes a femur bone, a tibia bone, a patella bone, and ligaments; and
 the patella remains in its native anatomical position during all steps of the method. 
 
     
     
         11 . The method of  claim 1  wherein the initial datum is referenced relative to at least one of the bones before any cuts or resections have been made. 
     
     
         12 . The method of  claim 1  wherein a difference is computed between the geometric position data collected and a final defined desired set of geometric position data. 
     
     
         13 . The method of  claim 12  wherein the computed difference is used to compute the desirable final best-fit position of an endoprosthesis with known geometry. 
     
     
         14 . The method of  claim 13  wherein the desirable best-fit position of the endoprosthesis is used to determine modifications to the bones that are carried out by tools with computed toolpaths relative to the primary datum. 
     
     
         13 . The method of  claim 12  wherein the magnitude of the difference is used to compute the inclusion of tensile members to supplement or augment the existing ligaments. 
     
     
         16 . The method of  claim 1  wherein the primary datum is positioned outside the joint, and each bone of the joint has a secondary datum associated therewith. 
     
     
         17 . The method of  claim 1  wherein the primary datum is fixed relative to one of the bones. 
     
     
         18 . The method of  claim 13  wherein the desirable best-fit position of the endoprosthesis is based on procedural outcomes from population data collected over time. 
     
     
         19 . The method of  claim 1  wherein an endoprosthesis is positioned relative to the bones of the joint from pre-operative measurement to assess joint kinematics. 
     
     
         20 . The method of  claim 1  wherein the positions of the implanted endoprosthetic components are stored digitally relative to primary and secondary datum positions of the joint for post-operative analysis of kinematic change over time or movement of the endoprosthetic components relative to the bones they were affixed to. 
     
     
         21 . The method of  claim 1 , wherein the digital geometric model is used to develop a patient-specific operative procedure. 
     
     
         22 . The method of  claim 1 , wherein the digital geometric model is used to develop a patient-specific endoprosthesis. 
     
     
         23 . The method of  claim 1 , wherein the digital geometric model is used to develop a patient-specific augmentation or replacement or repair, of a ligament or a tendon. 
     
     
         24 . The method of  claim 1 , wherein a digital display is used to portray the evaluated joint. 
     
     
         25 . The method of  claim 1 , wherein a virtual reality display is used to portray the evaluated joint.