What is Osteoarthritis?

 In a normal, healthy joint, a layer of smooth, rubbery tissue called cartilage lines the ends of each bone. Cartilage provides our joints with a firm but slippery cushioning surface, perfect for allowing the bones to glide against each other. It also acts as an important ‘shock absorber’ that protect our bones from damaging forces during physical movement.

When a joint is affected by OA, the cartilage in that joint breaks down and wears away. This exposes the bones underlying the cartilage and allows them to rub together, causing pain, swelling and reduced movement at the affected joint.

As this rubbing continues, the bones wear down and can change shape. Over time, small bits of jagged bone - called bony spurs or osteophytes - can grow on the edge of the bone and cause ‘crunching’ and ‘grinding’ within the joint.

The surrounding muscles and ligaments are also affected by the arthritis and they become weakened over time. This weakness could have contributed to the arthritis developing in the first place. When the muscles are not doing their job properly the joint cannot stay aligned and can start to move in directions it shouldn’t. Unfortunately this then makes the arthritis much worse.

This is a photo of severe base of thumb OA. As the joint subluxes it causes the middle thumb joint - the thumb knuckle - to bend too far backwards. This causes the whole thumb to have reduced movement, function and strength. It significantly impacts on function as you cant use your thumb the way you need to be able to.