Osteoarthritis (OA), also known as degenerative arthritis or degenerative joint disease,is the most common type of arthritis. It affects 10% of Canadians. Although OA can develop at any age, the risk increases with age and it usually develops after the age of 40.
Joints are located between 2 bones. The ends of each bone are covered by a tough, elastic material called cartilage. Cartilage protects the ends of the bones from damaging each other when they move.
In OA, the cartilage deteriorates, leading to joint damage, pain, and stiffness. OA is often referred to as a "wear and tear" disease, because over time, cartilage can weaken and break down, sometimes developing cracks and holes. Pieces of damaged cartilage can break off and irritate the joints or the tissues nearby. The joint pain and swelling caused by OA can make it painful and difficult to move.
Although any joint can be affected in OA, the hand joints and the weight-bearing joints of the hips, knees, feet, and spine are the most common. Other joints are not usually affected by OA, unless they have been injured or have experienced unusual stress.
What causes pain in OA?
Since there are no nerve endings in cartilage, the cartilage itself doesn't actually hurt. However, all the surrounding tissues such as tendons (inflexible cords that connect muscle to bone or other tissue) and ligaments (slightly elastic band of tissue which connects the ends of bones and prevents excessive movement of the joint) as well as bone can become inflamed (swollen, irritated, and painful). As the cartilage damage progresses, movements become more difficult and the other tissues such as tendons and ligaments must work harder to help keep the joints moving. Because tendons and ligaments are not designed to do this work, they become overworked, resulting in more inflammation in the joint. Eventually, the wearing of the cartilage may cause the bones to rub together, causing more pain. Bony growths (called spurs or osteophytes) that form as the bone thickens, also rub together, causing additional pain. This is especially common in weight-bearing joints like the hips, knees, and spine.
What are the usual symptoms of OA?
The most common symptoms of OA are joint pain, swelling, and stiffness.
OA is a progressive disease, and symptoms usually develop slowly, commonly involving the area around the joint. Over time, as the damage progresses, it may become painful to move the joint. It is common to hear grating sounds as the roughened surfaces of the cartilage rub together, creating bumps or swelling, especially in the small joints of fingers and feet.
What causes OA?
Although the exact cause is unknown, the older you are, the greater your chances of having OA. Heredity also may play a role, since some people who have OA also have other family members with it. Since being overweight can put stress on joints, it can increase your chances of getting OA, especially in the weight-bearing joints such as hips and knees. Overuse of the joint or repeated injury from work or sports can cause excessive or unusual wear and damage of their joints, and cause OA to develop. Joint damage from other types of arthritis, such as rheumatoid arthritis, can also increase the risk of OA.
How might OA affect my daily activities?
In addition to pain, inflammation, and visible joint deformities, joint damage from arthritis can make everyday activities such as walking, using a computer keyboard, or brushing your teeth a challenge.
Is there a cure for OA?
There is no cure for OA and treatments vary depending on the location and severity of the disease. The available treatments can help manage the condition, reduce pain and stiffness, and improve joint mobility. Treatments include medications, physiotherapy, exercise, weight loss, and surgery. Medications used for osteoarthritis include painkillers (analgesics) such as acetaminophen, non-steroidal anti-inflammatory drugs, corticosteroid injections into the joint, and capsaicin cream. Surgery is a last resort, and it is usually reserved for severe cases where the entire joint (often a hip or a knee) is worn, and needs replacement.
Written and reviewed by the MediResource Clinical Team