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    Osteoarthritis Health Center

    How Osteoarthritis Affects Your Knee

    Healthy Knee

    In a healthy joint, a rubbery tissue called cartilage cushions the ends of the bones at contact points. A thin, smooth tissue called the synovial membrane covers the other surfaces and releases a fluid that lubricates the knee.

    Thigh Bone

    The knee is one of the largest joints in the body, and one of the most complex. It is formed by the shin bone (tibia), the thigh bone (femur), and the knee cap (patella).

    Knee With Osteoarthritis

    Osteoarthritis in the knee begins with the gradual deterioration of cartilage. Without the protective cartilage, the bones begin to rub together, causing pain, loss of mobility, and deformity.

    Eroded Cartilage

    Cartilage becomes damaged and gradually wears away, allowing bone surfaces to rub together.

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