Minimally invasive surgery is a relatively new technology that allows surgeons to conduct surgeries without cutting as much tissue. The technique usually results in less pain, less scarring, shorter recovery time, and significantly reduced costs. Currently, University of Minnesota doctors at Fairview-University Medical Center are using the technology in a number of areas, including cardiac surgery, gynecologic surgery, and thoracic surgery. Recently, in some parts of the country, surgeons have begun to use minimally invasive surgery techniques to conduct knee replacement surgery. In a typical knee replacement surgery, surgeons cut the tissue of the extensor mechanism – which includes the quadriceps muscles, tendons, and surrounding soft tissues – and move it aside so that they can get down to deeper layers and perform the joint resurfacing operation. Cutting of this tissue involves more pain and more disability after surgery. However, most people eventually regain full knee function. The most important goal in a total knee replacement is pain-free or near pain-free function. The second goal is to have that joint resurfacing last as long as possible – ideally 20 years or longer. In order to accomplish the second goal and, arguably, even the first goal, you need precision cuts. You need the “carpentry work” to be perfect or near perfect. Most knee surgeons today are performing knee replacement surgeries using smaller incisions than they were 10 years ago. The next step is minimally invasive surgery, which involves viewing landmarks inside the knee through computer-guided technology. In this way, we can actually see the size of the bone and understand the angles of the cuts. I say understand because the technology allows us to see via the computer, not by actually visualizing them with our eyes. While this technology is not currently available in the Twin Cities for knee replacements, it will be here at the University of Minnesota within two years. Even with this image-guided technology, however, the procedure is not for most people who are in need of knee replacement. For overweight patients, finding the bone by using the computerized technology is less precise and increases the risk of an unsuccessful surgery. For patients with significant deformity or lack of motion, larger cuts are necessary to correctly align the knee and restore motion. What the patient should keep in mind is that regardless of how long it takes them to recover – whether two weeks or two months – a quick recovery is not worth it if it jeopardizes the longevity of the total joint. The minimal surgery technique for knee replacements has been employed in this country and Europe for less than five years. We do not yet know whether these knees will last as long as those done conventionally. If your bone cuts are accurate and your cementing technique is not jeopardized by smaller incisions, then the longevity of that joint should parallel the more conventional, larger incision technique. Each surgeon needs to make a patient-by-patient decision – sometimes even changing your technique on the operating table – to make sure that goal number two of long-lasting replacement is accomplished. Dr. Elizabeth Arendt is an orthopedic surgeon at the U of M Sports Medicine Institute. This column is an educational service and advice presented should not take the place of an examination by a health-care professional. To ask a health-care expert at the U of M a question or for more health-related information, go to www.healthtalkandyou.com/.
