Non-imaging, computer assisted navigation system for hip replacement surgery

A method of verifying reliability of a computer assisted, optically tracked surgical navigation system, comprising the steps of:

• fixing an optically trackable marker to a bone at a point of attachment;
• placing a mark on said bone at a location removed from said point of attachment;
• inputting an initial position of said mark into an optical tracking system by touching said mark with an optically trackable probe, while simultaneously tracking said optically trackable marker;
• calculating an initial vector locating said mark in the reference frame of said optically trackable marker;
• at a later time, inputting a later position of said mark into the optical tracking system by touching said mark again with the optically trackable probe, while simultaneously tracking said optically trackable marker;
• calculating a second vector locating the later position of said mark in the later reference frame of the optically trackable marker;
• and
• comparing said initial and said later vectors to verify that said optically trackable marker has remained fixed relative to said mark.