The majority of knee and hip replacement surgeries are necessary because the patient has severe osteoarthritis, a condition that occurs when the cartilage lining on the ends of bones gradually wears away. A standard knee implant typically lasts 10 to 15 years, but with people living longer and baby boomers staying active as they age, patients may be need to undergo the surgery more than once in their lifetime. In computer assisted surgeries, a knee implant is precisely aligned to minimize joint wear, potentially extending the life of the implant to up to 30 years.
Computer assisted joint replacement surgery captures a patient's unique anatomy and translates it to a computer screen, providing the surgeon with an unobstructed view of the patient's joint. First, the surgeon attaches temporary pins that hold markers that are read by the computer through an infrared camera. Next, they "teach" the computer about the patient by taking the joint through a range of motion. From this information, the computer generates a highly detailed, 3-D image of the joint's anatomy that assists the surgeon in determining where to cut the bone and how to place the implant as precisely as possible.
"In nearly 30 years of peer-reviewed orthopedic literature, it has been clear that the single most important determinant of long-term survival of a total knee or hip implant in a patient is the alignment of the implant. The more accurate the alignment, the longer the implant will last," says Gary M. Ferguson, MD, clinical director of the Total Joint Center. "Computer navigation allows us to bring the precision of bone cuts and implant alignment in joint replacement surgery to a whole new level of accuracy, reliability, and therefore, longevity."