Knee Arthritis
( Knee Pains )
Overview
Knee arthritis is inflammation and deterioration of knee joint cartilage. Cartilage is the slippery coating on the ends of bones that serves as a cushion and allows the knee to smoothly bend and straighten. Knee cartilage coats the end of the thighbone (femur), top of the shinbone (tibia) and the backside of the kneecap (patella). When cartilage wears away, the space between the bones narrows. In advanced arthritis, bone rubs on bone and bone spurs (bumps on the bone) may form.
Damage to the joint cartilage over time may result in the development or worsening of deformities of the knee, including knock knees and bowleg.
Symptoms
A knee joint affected by arthritis may be painful and inflamed. Generally, the pain develops gradually over time, although sudden onset is also possible. There are other symptoms, as well:
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The joint may become stiff and swollen, making it difficult to bend and straighten the knee.
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Pain and swelling may be worse in the morning, or after sitting or resting.
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Vigorous activity may cause pain to flare up.
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Loose fragments of cartilage and other tissue can interfere with the smooth motion of joints. The knee may "lock" or "stick" during movement. It may creak, click, snap or make a grinding noise (crepitus).
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Pain may cause a feeling of weakness or buckling in the knee.
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Many people with arthritis note increased joint pain with changes in the weather.
Causes
Cartilage loss can occur between the thighbone and the shinbone in the medial portion (inner side), lateral portion (outer side) and under the kneecap.
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Thinning of the cartilage under the kneecap (patella) is called patellofemoral arthritis (kneecap arthritis).
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Some patients have cartilage loss in one, two or all of these areas. When all three areas are affected, this is called tricompartmental arthritis.