Robotic Arm Reaches Out To Knee Surgeons

Orthopedic surgeons have found a helpful hand, or more precisely a robotic arm, that will allow them to perform more accurate knee surgeries. MAKO Surgical has released a Robotic Arm Interactive Orthopedic System that is designed to assist surgeons during knee resurfacing operations. This medical robotic arm has just been selected by R&D Magazine as a winner of the 48th Annual R&D 100 Awards, identifying it as one of the 100 most technologically significant products introduced into the marketplace over the past year.

More than 10 million Americans have knee osteoarthritis, and it is the most common cause of disability in the United States. Osteoarthritis occurs when the cartilage between two bones is worn down and the bones begin to directly rub against each other at the joint. The main problem for knees is the deterioration of the articular cartilage, the smooth lining that covers the ends of the leg bones where they meet to form the knee joint. This cartilage deterioration typically leads to pain, stiffness, limited range in motion of the knee, localized swelling, and the formation of bone spurs (small growths of new bone). The pain is usually worse after activity.

Knee osteoarthritis is diagnosed based on medical history, physical examination, x-ray imaging and possibly MRI (magnetic resonance imaging). Although many people with osteoarthritis don’t need surgery, in some cases surgery is required. Surgery may involve joint replacement in which the rough worn surfaces of the joint are replaced with a smooth artificial material, such as metal or plastic pieces.

Most people affected by osteoarthritis of the knee are older than 45 years. However, some younger active patients have early osteoarthritis. Such patients with arthritis in only one area of the knee can have partial knee resurfacing surgery, which is significantly less invasive than standard total knee replacement surgery. Partial knee resurfacing replaces only the deteriorated section of the knee with a small partial knee implant, without disturbing the knee’s healthy tissue. The benefits of this less invasive surgery can be significant: smaller incision, less bone removed, less discomfort, shorter hospital stay, less physical therapy required, and more rapid healing. Since less bone is removed (about 0.25” instead of 0.5”), future total knee replacement surgery can also be more easily performed, if necessary.

However, partial knee resurfacing can be a difficult operation to perform. Using the MAKO robotic arm system to assist with the surgery will hopefully provide increased stability and precision. It also allows the surgery to be performed for a greater number of patients, since it allows the replacement of the top (patellofemoral) portion of the knee joint instead of just the inner (medial) or outer (lateral) portion. The system provides patient-specific, pre-surgical planning with 3-D modeling based on CT (x-ray computed tomography) images. The system also provides real-time visual, tactile and auditory feedback during the surgery. This should enable the orthopedic surgeons to more precisely position the partial knee implants. Hopefully this new technology will help provide a more natural feeling artificial knee and a healthier active lifestyle to some people that suffer from knee osteoarthritis.

Author: Jennifer Huber

As a Ph.D. physicist and research scientist at the Lawrence Berkeley National Laboratory, I gained extensive experience in medical imaging and technical writing. Now, I am a full-time freelance science writer, editor and science-writing instructor. I've lived in the San Francisco Bay Area most of my life and I frequently enjoy the eclectic cultural, culinary and outdoor activities available in the area.

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