Computers have been assisting surgeons in the operating room since the 1980s. Today approximately 7% of all joint replacement surgeries are completed with the aid of computer navigation technology. Similar to the GPS in your car, these devices guide surgeons to precisely position the components of a hip or knee replacement. These tools can help surgeons decide what thickness of bone to remove and how to improve limb alignment. In theory, a well-balanced and properly aligned joint replacement should, like your new car tires, last longer if in acceptable alignment. The number of joint replacements done with this technology may grow over the next decade as it continues to improve.