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Custom-Designed Knee Replacement is Literally What Doctor Ordered Less Invasive Joint Replacement Surgery Gets Patients Back on their Feet Faster

(New York, N.Y. April 2005.) The term "custom-designed" usually brings to mind jewelry, clothing or kitchen cabinets. Now a new option for certain patients with severe knee pain is giving new meaning to the term. Dr. Geoffrey Westrich at the Hospital for Special Surgery in Manhattan is performing partial joint replacement surgery using a custom-designed knee implant, or prosthesis. "The made-to-order prosthesis is for patients whose arthritis is limited to their patella, or kneecap," Dr. Westrich says. "Instead of replacing the total joint, we replace only the arthritic area of the knee to relieve pain and help patients return to activities they may have abandoned. The less extensive procedure results in less post-operative pain, a shorter hospital stay and a quicker recovery. Most important, it preserves the normal bone and cartilage in the rest of the knee which would typically be replaced with a total knee replacement."

The first step is to see whether a patient is a candidate for the procedure. Once Dr. Westrich determines that the arthritis is limited to the knee cap, a high-tech CT scan takes detailed pictures of the patient's knee joint. The pictures are then transferred to a CD-rom and sent to the manufacturer, who designs a model of the prosthesis and sends it to Dr. Westrich for review. Once he provides feedback, the custom-made kneecap takes about four weeks to manufacture.

The diagnosis is key, as the knee is divided into three compartments -- medial, lateral and patellofemoral (kneecap region)-- and arthritis can involve one, two or all three areas. An estimated 21 million Americans have osteoarthritis, in which cartilage wears away, resulting in pain and a loss of mobility. Until recently, when more conservative treatments failed, the best option for patients with advanced arthritis was to resurface all three compartments with a total joint replacement. Such surgery generally entails extensive physical therapy, and it can take months for patients to regain full function of their knee joint.

Custom patellofemoral knee replacement surgery is an easier alternative for patients whose arthritis is caused by worn cartilage under the kneecap. "The partial, custom joint replacement is a much less invasive procedure," Dr. Westrich says. "There is a 3 to 4-inch incision, as opposed to 5 to 6 inches, patients experience less pain right after surgery, and physical therapy and recovery are faster," he says. The hospital stay is also reduced, from five to six days for a total joint replacement to 2 to3 days for the more limited procedure. Many patients who have the custom joint replacement can get out of bed and walk on their knee the day after surgery, and within two weeks they can progress to more normal activities.

"For the new procedure, the average patient is their 40's or 50's, has arthritis pain in the front of their knee and wants to get back to activities arthritis has forced them to give up," Dr. Westrich says. When someone comes in with knee pain, he initially prescribes non-surgical treatments, such as anti-inflammatory medication and mild exercises or physical therapy. When these treatments fail and pain persists, patients consider joint replacement.

Currently, about 300,000 knee replacements are performed in the United States each year. With the aging of the baby boomer population, Dr. Westrich expects the number to rise, and the partial, custom knee replacement may be a viable option for many.

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