Of the more than 15 million Americans diagnosed with osteoarthritis in the knee, approximately 600,000 could be helped by undergoing a partial knee replacement. And now they may also be aided by a new robotic technology developed by MAKO Surgical Corp. of Fort Lauderdale, FL. A team of biomedical engineers led by Rony Abovitz has developed a precision knee resurfacing system in which surgeons use a robotic arm to resurface the knee - before the implant is placed. "What we're doing now is a stage before you'd replace an entire knee," says Abovitz, who explains that the system makes knee resurfacing so precise that patients are able to recover faster and with less pain. "They're walking naturally and back to work in a couple days," he adds.

Before the resurfacing can be performed, a 3-D image of the knee is created, so that surgeons have a "live-action view" as they manipulate the robotic arm. The image is continuously updated throughout the procedure, pinpointing the exact location of the diseased area to ensure that healthy bone and tissue are protected. Audio and visual alarms sound should the surgeon get too close to the "no-go zone." The robotic arm also generates artificial resistance, so that surgeons feel like they are "hitting a wall" should the robotic arm come too close to the healthy parts. "Your hand feels like it's basically touching a real wall, and you get this sensation of being blocked," says Abovitz. Once the diseased area has been resurfaced, the surgeon places the implant. Most patients are able to literally walk out of the hospital the same day of surgery.

Osteoarthritis of the knee typically occurs in people who have experienced trauma, infection or injury. The condition develops as the articular cartilage in the knee, which acts as a protective cushion between the bones, begins to deteriorate. As the cartilage diminishes, the joint space between the bones narrows. In severe cases, when the articular cartilage is gone, the thickened bone ends rub against each other and wear away, which can result in joint deformity. Even performing normal activities like walking can become painful and difficult. Hereditary factors, as well as weight issues and advancing age, can also lead to osteoarthritis of the knee. Click on the link below to view a video of the procedure.

News Release: Fixing damaged knees - Biomedical engineers arm surgeons for highly precise knee resurfacing with robot www.sciencedaily.com  January 2009