What is arthritis?
Knee pain and arthritis
Knee pain can be short-lived (acute) or persistent (chronic). Pain results from tissue damage and when it is persistent, it could be a sign of long-term damage sustained in an injury or by an underlying problem within the joint.
Arthritis, which means ‘inflammation within a joint’, is the most common cause of chronic knee pain. Arthritis can affect people of all ages, sexes and races but occurs more frequently as people get older. Over a third of the population over the age of 50 has arthritis pain that interferes with their normal activities1. Although the word is widely used to describe pain, swelling or stiffness in a joint, there are many types of arthritis which can be caused by inflammatory, mechanical or degenerative conditions.
Osteoarthritis is the most common type of arthritis. It is a condition where the smooth and lubricated cartilage that protects the ends of the bones becomes worn or damaged. Cartilage can become thin and rough and in response to the damage the joint can develop bony spurs. This causes pain, swelling and can restrict knee joint movement. It is not known what causes osteoarthritis, but several factors are thought to increase the risk of developing it:
- previous injury,
- getting older,
- being overweight (obese),
- certain hereditary factors,
- other health conditions such as rheumatoid arthritis or gout.
Along with hip osteoarthritis, knee osteoarthritis is one of the leading causes of global disability2.
Rheumatoid arthritis is a disease where the body’s immune system attacks the joints causing pain, swelling and stiffness. In addition to joint problems, rheumatoid arthritis can affect other parts of the body such as the lungs and kidneys and cause symptoms such as:
- weight loss,
- loss of appetite.
Other Types of Arthritis
Chronic knee pain can also be due to:
- bone growth disorders (dysplasia),
- blood supply problems (avascular necrosis),
- knee injury,
- knee deformity.