Replacing knees with 3-D

BACKGROUND: Knee replacement surgery, also known as knee arthroplasty, is a surgical procedure used to replace a damaged knee joint, usually due to arthritis, with an artificial knee.  Artificial joints are designed to mimic the knee's natural rolling; gliding motion and a wide variety of options allows the surgeon to customize the joint according to one's body, age and activity level.  The most common cause of knee joint replacement is to repair joint damage caused by osteoarthritis and rheumatoid arthritis.  Candidates for knee replacement surgery are people who have trouble walking, climbing stairs, and getting in and out of chairs.  They may also experience sever knee pain at rest.  A knee deformity is also another good reason for knee surgery.  This surgery is also typical for people who are 55 or older.  (www.mayoclinic.com)

SHAPEMATCH: Shapematch technology used by Stryker was created to help orthopedic surgeons fit and position knee implants based on the individual's anatomy.  The procedure is achieved by first having an MRI, Magnetic Resonance Imaging, that scans and records detailed images of the knee.  Second, the proprietary software utilizes the MRI images to create a three-dimensional knee model.  Then the implant size and positioning is determined using the 3D model of the knee.  With the pre-surgical model completed, the surgeon reviews the specifications based on Shapematch Technology.  Following approval, customized guides are then used in the operating room.  (www.aboutstryker.com)

APPLICATION: Stryker knee replacements are designed to work with the body to promote easier motion.  The knee replacements are designed with a single radius, which means that as the knee flexes, the radius is the same, similar to a circle, requiring less effort from the thigh muscle.  Since the thigh muscle, or quadriceps, is attached to the knee it is unavoidably involved in the surgery.  Therefore, the quadriceps muscle can become a source of pain or discomfort post surgery.  The durability of the knee implants depends on many things including the patient's weight and activity level, as well as the implants bearing surface technology.  The bearing surface is defined as the two parts of the knee that glide together throughout motion.  However, Stryker developed the Triathlon Knee System with X3 Advanced Bearing technology and based on laboratory testing, the technology only offered by Stryker has had a lower wear rate which may result in a longer lasting implant. (www.aboutstryker.com)