The healthy knee is a hinge joint. The three bones that form the knee are the thighbone (femur), shinbone (tibia), and kneecap (patella). The femur and tibia are held together by ligaments, which are strong bands of tissue that stabilize the joint. The end of the femur, the top of the tibia, and the back of the patella are covered with a tough lubricating tissue called cartilage. Cartilage acts like a natural shock absorber, preventing both bone on bone contact and providing a smooth, pain-free surface for the bones to glide against. The knee also contains synovial membranes, which produce synovial fluid to help lubricate and nourish the cartilage.
 Healthy Knee |
 Partial Knee Arthritis |
 Total Knee Arthritis |
Knee cartilage can be compared to the tread of an automobile tire, very durable but susceptible to wear over time. Osteoarthritis is a degenerative process, which results in the wearing out of the cartilage that protects the bones in the joints. As we age, the tread surface slowly erodes until the underlying bone is exposed. This exposed bone can be painful when the joint moves and bears weight.
Arthritis is a term that is used to describe over 100 different kinds of conditions that can affect the human body. Arthritis affects millions of Americans each year with symptoms including pain, stiffness, swelling, and loss of motion in affected joints.
Patient Education information provided by Biomet, Inc. - Advanced Science for Real Living™