Patent ID: 7634306

Claim:
A computer assisted surgical method of fitting a customizable modular hip implant system in a hip arthroplasty procedure, comprising the steps of: intraoperatively mounting an optically trackable marker to a femur; intraoperatively measuring the position of a native femoral head center (Cl) in relation to said optically trackable marker, by tracking the position and orientation of said optically trackable marker via an optical locating system interfaced with a digital computer, while moving the hip joint through a motion consistent with a natural arc of movement; placing a stem component of the modular hip implant system in the femur; with said optical locating system interfaced with said digital computer, optically and substantially simultaneously tracking both said optically trackable marker and said stem component placed in the femur, to intraoperatively measure the relative position and orientation of said stem component in relation to said optically trackable marker; calculating the position and orientation of said stem component in relation to said optically trackable marker, based on the substantially simultaneously measured relative positions and orientations of said stem component and said optically trackable marker; determining a desired position for a prosthetic femoral head center (C 2 ); transforming the desired position for said desired prosthetic femoral head center (C 2 ) into a stem coordinate system defined in relation to said stem component; and selecting, with the aid of a digital computer at least one combination of implant modules which will combine with said stem component to fix a prosthetic femoral head center at the desired position (C 2 ).