System and method for bone preparation for an implant

Abstract

A computer assisted surgical system for guiding bone cutting operations of an arthroplasty surgery is provided. The computer assisted surgical system includes a cutting guide having a guiding surface for mounting to a bone and a computer. The computer is in communication with the cutting guide and configured to generate a bone model of the first bone without the use of pre-operative bone images, determine a position of an implant model having a bone interface surface on the bone model, determine a position of the cutting guide on the first bone based on the determined position of the implant model on the bone model, and position the guiding surface of the cutting guide to one of a plurality of predetermined cut configurations relative to the bone interface surface.

I/We claim: 
     
         1 . A computer assisted surgical system for guiding bone cutting operations of an arthroplasty surgery comprising:
 a cutting guide to be positioned relative to a first bone; and   a computer having a plurality of predetermined cut configurations corresponding to various degrees of interference fit of an implant on the first bone, and wherein the computer is in communication with the cutting guide and configured to position the cutting guide to one of the plurality of predetermined cut configurations.   
     
     
         2 . The system of  claim 1 , wherein the plurality of predetermined cut configurations is relative to a bone interface surface of the implant. 
     
     
         3 . The system of  claim 1 , wherein the computer is further configured to
 generate a bone model of the first bone without the use of pre-operative bone images,   determine an optimum position of an implant model having a bone interface surface on the bone model, and   determine a position of the cutting guide relative to the first bone based on the determined position of the implant model on the bone model.   
     
     
         4 . The system of  claim 1 , wherein the computer is further configured to intra-operatively receive a selection of one of the plurality of predetermined cut configurations and position the cutting guide to a position corresponding to the selected predetermined cut configuration. 
     
     
         5 . The system of  claim 1 , wherein the plurality of predetermined cut configurations is a plurality of predetermined planes parallel to or at an angle relative to a bone interface surface of the implant. 
     
     
         6 . The system of  claim 5 , wherein the plurality of predetermined planes parallel to the bone interface surface is co-planar to the bone interface surface to provide a congruency fit or the plurality of predetermined planes is offset from the bone interface surface to provide an interference fit. 
     
     
         7 . The system of  claim 1 , further comprising a display for displaying the plurality of predetermined cut configurations. 
     
     
         8 . The system of  claim 7 , wherein the computer is further configured to display planned resection contours corresponding to one of the plurality of predetermined out configurations on the display. 
     
     
         9 . The system of  claim 7 , wherein the display includes a representation of a degree of interference between the implant model and bone model. 
     
     
         10 . The system of  claim 9 , wherein the representation is a color map and various colors of the color map are representative of varying degrees of interference fit. 
     
     
         11 . The system of  claim 7 , wherein the computer is further configured to allow a user to intra-operatively select one of the plurality of predetermined cut configurations displayed on the display. 
     
     
         12 . The system of  claim 1 , wherein the computer is further configured to allow a user to align the cutting guide to another one of the plurality of predetermined cut configurations after an initial cut of the first bone. 
     
     
         13 . A method of preparing a bone for an implant during an arthroplasty comprising the steps of:
 providing a computer assisted surgery system having a plurality of predetermined cut configurations;   selecting a degree of interference fit between an implant and a bone that corresponds to one of the plurality of predetermined cut configurations; and   positioning a cutting guide to one of a plurality of predetermined cut configurations corresponding to the selected degree of interference.   
     
     
         14 . The method of  claim 13 , further comprising the steps of:
 generating a bone model of a bone;   providing an implant model having a bone interface; and   determining an optimum position of the implant model on the bone model,   wherein the cutting guide is positioned relative to the bone based on the determined optimum position.   
     
     
         15 . The method of  claim 13 , wherein selecting the degree of interference fit between the implant and bone is based on an intra-operative evaluation of a quality of the bone. 
     
     
         16 . The method of  claim 13 , further comprising the steps of:
 resecting the bone at a plane corresponding to the positioned cutting guide:   intra-operatively evaluating a quality of the resected bone; and   selecting another degree of interference fit between the implant model and the bone model based on the intra-operative evaluation of the resected bone.   
     
     
         17 . The method of  claim 14 , wherein the bone model is generated without the use of pre-operative bone images. 
     
     
         18 . The method of  claim 14 , wherein the bone model is generated using a computer assisted surgical system in communication with and operably connected to the cutting guide. 
     
     
         19 . A method of preparing a first bone for an implant during an arthroplasty comprising the steps of:
 providing a computer assisted surgery system having a set of default user preferences for resecting bone that corresponds to an interference fit of a prosthesis on the first bone;   positioning a cutting guide in communication with the computer assisted surgery system relative to the first bone;   aligning the cutting guide to correspond to the default user preferences for resecting bone;   intra-operatively evaluating a quality of the first bone; and   determining if a repositioning of the cutting guide from the default user preferences is required.   
     
     
         20 . The method of  claim 19 , wherein the computer assisted surgery system has a plurality of implant models in memory and is further configured to generate a bone model of the first bone, and wherein the method further comprises the step of selecting an implant model and determining an optimum position of the implant model on the bone model.