Osteoarthritis (OA) is a condition that affects the joints.
In a normal joint, the ends of the bones are covered by a layer of cartilage. Cartilage helps the joint move smoothly and cushions the ends of the bones.
In OA, the cartilage breaks down and becomes thin. This leaves the ends of the bones unprotected, and the joint loses its ability to move smoothly.
OA mainly affects people over the age of 45, but it can develop in younger people.
Osteoarthritis is different from osteoporosis. Osteoporosis is a condition where the bones become fragile and brittle, causing them to break more easily.
What are the symptoms?
The symptoms of OA vary from person to person. Your symptoms will also depend on which joints are affected. OA tends to come on slowly, over months or even years. The most common symptoms are pain and stiff ness of the joints. These feelings are usually worst after resting or not moving the joint for a while. These symptoms may affect the ability to do normal daily activities, such as walking, climbing stairs and opening jars.
What causes it?
In many people there is no clear cause of OA. Research shows there are some things that may put you at more risk of developing OA in certain joints, such as:
- knees: being overweight, having a previous knee injury, jobs involving kneeling, climbing and squatting
- hips: being overweight, having a previous hip injury, jobs involving lifting heavy loads (including farming)
- hands: having a history of OA in the family
How is it diagnosed?
Your doctor will diagnose OA from your symptoms and a physical examination. An x-ray may show the joint space narrowing and changes in the shape of your joint. However x-rays do not diagnose how much trouble you will have. An x-ray that shows joint damage does not always mean you will have a lot of pain or problems. On the other hand your joint may be very painful despite x-rays being normal. Blood tests are only helpful to rule out other types of arthritis.
What treatments are there for OA?
Treatments for OA vary depending on which joints are affected and the severity of your condition. There is no way of predicting exactly which treatment will work best for you. Each treatment has its own benefits and risks. Your doctor may need to trial several different treatments before finding the one that is right for you.
In general terms, treatment usually includes:
- simple pain relief, using medicines such as paracetamol
- non-steroidal anti-inflammatory drugs (NSAIDs)
- an exercise program designed to suit your needs
- a weight loss program, if you are overweight
- joint replacement surgery, if your symptoms are no longer controlled with other therapies.
What is rheumatoid arthritis?
Rheumatoid arthritis affects the synovial membrane that surrounds the joint.
For reasons not fully understood, the body’s immune system attacks (autoimmune disease) the membrane causing inflammation and an over-production of synovial fluid. The membrane is invaded by white blood cells, which produce a variety of destructive chemicals. The cartilage along the articular surfaces of the bones may be attacked and destroyed. This process causes joints to become swollen and painful. If the process continues, damage to the cartilage can cause joint deformities.
Other problems throughout the body (systemic problems) may also develop including inflammation of blood vessels, the development of bumps (rheumatoid nodules) in various parts of the body, lung disease, blood disorders and weakening of the bones (osteoporosis).