Computer-assisted surgery allows surgeons to align the patient's joint replacement with a degree of accuracy not possible with the naked eye.  This technology can be used with both hip replacements and knee replacements.  Using an infrared camera and sensors on the instruments, the computer gives real-time feedback to the surgeon.  The computer tells the surgeon how much bone is being cut to the millimeter and what angle the bone is being cut to a fraction of a degree.

By placing hip and knee implants more accurately they should last longer and allow the joint replacement to function more properly.