Jason E. Lang, M.D., an assistant professor of orthopaedic surgery, will perform a computer-assisted total knee replacement during a live webcast that begins at noon, Friday, May 2, from Wake Forest University Baptist Medical Center.
William G. Ward, M.D., an orthopaedic surgeon who also performs joint replacements, will narrate the procedure and take questions from Internet viewers.
Knee replacement surgery is for patients who have extreme knee pain and disabilities caused by congenital defects, trauma, osteoarthritis or rheumatoid arthritis. Cartilage may have worn away and the patient's thigh and shin bones rub directly against each other. Knee replacement patients typically have already tried non-steroidal anti-inflammatory drugs, cortisone injections, physician therapy and even less invasive surgeries to relieve their discomfort.
During the surgery, the physician trims off about one third of an inch of the ends of the thigh bone and then cements a curved metal femoral component that covers the end of the thigh bone. About a third of an inch of the shin bone is trimmed away at the top and replaced with a flat and stemmed tibial plate that is cemented onto the top of the shin bone. The plate has a polyethylene cushion that allows for movement. Another piece replaces the patella or kneecap.
The metal pieces are typically titanium- or cobalt chromium-based alloys. These replacement joints have a 95 percent chance of lasting 10 to 20 years or more. Before and during surgery, the physician uses the computer to take measurements that guide the size, design and placement of the knee joint.