Osteoarthritis can be grouped into two types, primary and secondary.
In primary, the cause is generally unknown and in secondary it can develop following damage to the joint or mis-alignment.

When osteoarthritis develops the surface of the cartilage splits, and focal erosions develops leading to exposure of the underlying bone. The exposed bone becomes worn and smooth. This is called eburnation. The synovial fluid can enter the exposed bone and if this happens, cysts (subchondrial cysts) can develop.

Osteophytes develop around the joint margin. The joint becomes unstable as the capsule becomes lax and muscles wasting develops. Effusion and inflammation may be due to trauma or irritation.

Primary Osteoarthritis: The cause is unknown but factors such as ageing, cartilage wear, obesity, metabolic disturbance, bone wear and genetic factors should be considered. It is most common in the elderly but can develop in young people. Obesity is an important factor. Additional weight will create extra pressure on joints and lead to wear. In primary osteoarthritis the ankle joints are spared.

Secondary Osteoarthritis: Damage or mal-alignment following trauma can lead to premature wear of joints.

Trauma: This can be intra-articular fracture and can cause mal-alignment, in the lower limb or a shorter leg. All these can contribute to extra wear. Occupation also contribute to trauma ie footballers are likely to have ankle injuries.

Genetic: These include bone and cartilage dysplasia, congenital dislocation of the hip, Perthe’s disease, slipped femoral epiphysis, and hypermobility joints.

Inflammation: Includes septic arthritis, rheumatoid arthritis and gout.

Bone Disorder: Aseptic Necrosis and pagets’ disease.

Other Conditions: Haemophilia can lead to osteoarthritis.

Dr. Phil Hariram

Arthritis Treatment.