For many years, it was commonly believed that osteoarthritis (OA) was just the result of normal wear and tear of the joints. But it’s not that simple. While it’s generally accepted that overweight, overuse of certain joints, injuries to particular joints, and the process of ageing play a role in the development of primary OA, the actual cause of most cases of primary OA isn’t really known.
Secondary OA develops when certain conditions change the micro-environment of the cartilage. These can include genetic defects, and improperly formed joints.
Secondary OA can also be caused by certain metabolic disorders, such as haemochromatosis. Infectious processes and some neurological diseases can also affect the complex system of the joints.
OA, especially of the end joints in the fingers and the spine, tends to run in families.
Reviewed by Dr Stella Botha, rheumatologist at Groote Schuur Hospital, Cape Town (MBChB, MRCP, PhD), November 2017.