What is knee osteoarthritis?

Osteoarthritis is characterized by chronic and often disabling pain and stiffness of one or more joints, particularly those of the fingers, spine, hips, knees, and feet. Osteoarthritis is the most common form of arthritis and was once called degenerative joint disease. Most people who are affected by osteoarthritis are middle-aged or older.

Also known as Knee Osteoarthritides
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Osteoarthritis, sometimes called degenerative joint disease or osteoarthrosis, is the most common form of arthritis. Osteoarthritis occurs when cartilage in your joints wears down over time.



Osteoarthritis is not a single disease but rather the end result of a variety of disorders leading to the structural or functional failure of 1 or more of your joints. Osteoarthritis involves the entire joint including the nearby muscles, underlying bone, ligaments, joint lining (synovium), and the joint cover (capsule). Osteoarthritis also involves an advancing loss of cartilage. The cartilage tries to repair itself, the bone remodels, the underlying (subchondral) bone hardens, and bone cyst form. This process has several phases. The stationary phase of disease progression in osteoarthritis involves the formation of osteophytes or joint space narrowing. Osteoarthritis progresses further with obliteration of the joint space. The appearance of subchondral cysts (cysts in the bone underneath the cartilage) indicates the erosive phase of disease progression in osteoarthritis. The last phase in the disease progression involves bone repair and remodeling. Definitions Joint cartilage is a layer of tissue present at the joint surfaces that sustains joint loading and allows motion. It is gel-like, porous, and elastic. Normal cartilage provides a durable, low-friction, load-bearing surface for joints. Articular surface is the area of the joint where the ends of the bones meet, or articulate, and function like a ball bearing. Bone remodeling is a process in which damaged bone attempts to repair itself. The damage may occur from either an acute injury or as the result of chronic irritation such as that found in osteoarthritis. Collagen is the main supportive protein found in bone tendon, cartilage, skin, and connective tissue. Osteophytes are bony outgrowths or lumps, especially at the joint margins. They are thought to develop in order to offload the pressure on the joint by increasing the surface area on which your weight is distributed. Synovium is a membrane found within the joints that secretes a fluid that lubricates tissues where friction would otherwise occur. Subchondral bone is the part of bone under the cartilage.


It is not possible to prevent osteoarthritis altogether. However, you may be able to minimise your risk of developing osteoarthritis by avoiding factors that can make developing it more likely.


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Osteoarthritis (OA) is the most common joint disorder.

Knee Injury
The knee has a simple purpose. It needs to flex (bend) or extend (straighten) to allow the body to perform many activities like running, walking, kicking, and sitting. Imagine standing up from a chair if your knees couldn't bend.

Knee pain
Pain - knee

Your knee joint is made up of bone, cartilage, ligaments and fluid. Muscles and tendons help the knee joint move. When any of these structures is hurt or diseased, you have knee problems. Knee problems can cause pain and difficulty walking. Arthritis is the most common disease that affects bones in your knees. The cartilage in the knee gradually wears away, causing pain and swelling. Injuries to ligaments and tendons also cause knee problems. A common injury is to the anterior cruciate ligament (ACL). You usually injure your ACL by a sudden twisting motion. ACL and other knee injuries are common sports injuries.

Knee bursitis
Bursitis (ber-SEYE-tis) is swelling and pain of a bursa. A bursa is a fluid-filled sac that acts as a cushion or shock absorber between a tendon and a bone. A tendon is a cord of tough tissue that connects muscles to bones. Normally a bursa has a small amount of fluid in it. When injured, the bursa becomes inflamed (red and sore) and may fill with too much fluid. When you have an inflamed bursa in your patellar (pah-TEL-er) or kneecap area, you have knee bursitis. You may have inflammation (in-flah-MAY-shun) in front of or behind the kneecap. You may also have it on the inner sides of your knees (where they may knock together).

Knee braces
Discuss your interest in knee braces with your doctor. Together you can weigh the benefits and risks of knee braces to decide whether they are right for you.

Knee Sprain
A knee sprain occurs when one or more ligaments in your knee are suddenly stretched or torn. Ligaments are tissues that hold bones together. Ligaments support the knee and keep the joint and bones lined up. They help you to be able to walk, twist and turn. There are four ligaments that help support the knee. Ask your caregiver which of these ligaments was sprained in your knee. Ligaments are often sprained because of an exercise or sports-related injury. Treatment and recovery time depend on the type and cause of the knee sprain.

Knee MRI scan
A magnetic resonance imaging (MRI) scan of the knee is a noninvasive way to take pictures of the knee joint and surrounding muscles and other tissues. Unlike x-rays and computed tomographic (CT) scans, which use radiation, MRI uses powerful magnets and radio waves. The MRI scanner contains the magnet. The magnetic field produced by an MRI is about 10 thousand times greater than the earth's. The magnetic field forces hydrogen atoms in the body to line up in a certain way (similar to how the needle on a compass moves when you hold it near a magnet). When radio waves are sent toward the lined-up hydrogen atoms, they bounce back, and a computer records the signal. Different types of tissues send back different signals. Single MRI images are called slices. The images can be stored on a computer or printed on film. One exam produces dozens or sometimes hundreds of images.

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