Robotic guide assembly for use in computer-aided surgery

Abstract

A system for guiding resurfacing operations on at least a portion of a joint of at least one bone is provided and uses a guide with actuators (motors) controlled by a computer to position a cutting tool relative to a bone so that the bone surface can be cut in a flexible and accurate manner.

1 - 14 . (canceled) 
     
     
         15 . A method for performing computer assisted knee arthroplasty comprising:
 tracking a position of a femur and a tibia of a knee joint using a position measuring system;   creating a three-dimensional surface model of the femur using a computer having computer instructions stored in a memory executable by a processor to acquire data points from a pointer tracked by the position measuring system, wherein the data points are various points on a surface of the femur used in defining the three-dimensional surface model of the femur;   performing ligament gap assessment between the tibia and femur at various flexion angles of the knee joint;   determining, with the use of the computer,
 an optimal position and size of a femoral implant for implantation on the femur based on the three-dimensional surface model of the femur and ligament gap assessment at various degrees of flexion of the knee joint, and 
 positions of cutting planes corresponding to the optimal implantation position of the femoral implant on the femur; 
   attaching to the femur a robotic cutting system in communication with the computer; and   aligning a cutting guide of the robotic cutting system to each of the cutting planes corresponding to the implantation position of the femoral implant on the femur.   
     
     
         16 . The method of  claim 15 , further comprising the step of resecting the tibia before performing ligament gap assessment. 
     
     
         17 . The method of  claim 15 , further comprising validating the position and size of the femoral implant using the three-dimensional surface model of the femur displayed on a display screen of the computer. 
     
     
         18 . The method of  claim 17 , further comprising updating at least one of the optimal position and size of the femoral implant for implantation on the femur after the step of validating. 
     
     
         19 . The method of  claim 15 , further comprising validating the position and size of the femoral implant using the three-dimensional surface model of the femur displayed on a display screen of the computer overlaid with the positions of the cutting planes corresponding to the optimal implantation position of the femoral implant on the femur. 
     
     
         20 . The method of  claim 15 , further comprising:
 creating a three-dimensional surface model of the tibia using the computer having computer instructions stored in a memory executable by a processor to acquire data points from the pointer tracked by the position measuring system, wherein the data points are various points on a surface of the tibia used in defining the three-dimensional surface model of the tibia;   attaching a navigated tibial cutting guide to the tibia; and   resecting the tibia using the navigated tibial cutting guide.   
     
     
         21 . The method of  claim 15 , wherein the step of aligning the cutting guide includes rotating the cutting guide between the cutting planes about a fixed distance from a rotational axis of the robotic cutting system. 
     
     
         22 . The method of  claim 15 , wherein the step of attaching includes attaching the robotic cutting system to a medial side of the femur. 
     
     
         23 . The method of  claim 15 , further comprising resecting the femur along at least one of the cutting planes and positioning the cutting guide directly against a resected surface of the femur. 
     
     
         24 . The method of  claim 15 , wherein the step of performing ligament gap assessment includes recording ligament gap assessment values of the tibia and femur at various flexion angles of the knee joint on the computer. 
     
     
         25 . The method of  claim 15 , wherein the step of creating the three-dimensional surface model of the femur includes deforming a generic surface model based on the acquired data points. 
     
     
         26 . The method of  claim 15 , wherein the step of creating the three-dimensional surface model of the femur includes matching medical image data to the acquired data points. 
     
     
         27 . The method of  claim 15 , wherein the pointer is an ultrasound probe.