Osteoarthritis (OA) is a common joint disease due to wear and tear of joint cartilage. The joints most commonly affected are those of the hips, knees, hands, big toe, and spine..Osteoarthritis (OA) is the most common form of arthritis, affecting around 8 million people in the UK. Anyone can get OA however it is more common in women, those over 40 and if you are overweight. It is also more common if you have a manual job where you do repetitive movements or lift heavy objects which can put excess strain on the joints. Additionally, OA is more likely if there has been a previous injury to that joint or if the joint was damaged by another disease. This includes diseases such as gout or rheumatoid arthritis but also congenital defects of the joint (i.e. defects you are born with) or joint diseases that develop in childhood e.g. Perthes’ disease of the hip.
Genetic factors also play a role in OA therefore it is more common in those with a family history of OA. Genetic factors seem to be more common in those with a form of OA of the hands called nodal osteoarthritis which is more common in women. This causes nodules in the hands that are often very painful. There is also some evidence to show that rarer forms of arthritis that start at an earlier age may be related to genetic defects in collagen (one of the key components of cartilage). Genetic factors play a smaller, but still significant, part in osteoarthritis of the hip and knee also.
OA is a chronic, progressive disease. The joints usually have cartilage, a protective lining called synovium and a fluid called synovial fluid. These provide a smooth, low-friction surface between the ends of bones. When cartilage loses its elasticity and wears down, joint movement becomes less smooth. Eventually, cartilage can completely erode and the opposing bone ends rub together. This can cause the formation of new bone spurs called osteophytes at the edges of the joints. The synovium can also swell and thicken causing swelling of the joint. In addition the ligaments and connective tissue around the joint can thicken and contract as they try to stabilise the joint.
In view of these changes the most common symptoms of OA are pain usually at the end of the day or when moving the joint; stiffness that is worse in the morning and/or after rest and joint swelling. The wearing down of the bones if cartilage is lost, and the bony spurs, can also cause the shape of the joint to change. This will then affect its function. Therefore, in addition to pain and stiffness, the joint may not move as well or as far as normal. The muscles around the joint may also appear thin and wasted. This may cause the joint to “give way” or collapse when using it. The pain with OA may be intermittent but may become constant. In addition some people report that their pain is worse with cold or damp weather or if they have done a lot of exercise or activity.