Arthritis is inflammation within a joint and there are two main categories, osteoarthritis and rheumatoid arthritis. The distinction is made because the cause of the inflammation is completely different with the two conditions.

With rheumatoid arthritis, the inflammation is an autoimmune phenomenon in that the body’s only immune system attacks and destroys the joints in the body. We don’t understand what initiates this process and therefore we can’t cure it. Typically, it affects the small joints of the hands and the feet.

Rheumatoid arthritis will not be discussed further in this presentation as there is no evidence that it is more common in patients who are suffering from obesity. It is therefore beyond the remit of this forum.

Osteoarthritis is inflammation of the joints characterised by “wear and tear”. It tends to affect the major joints of the body, ie the joints that typically that have to do more work, so we are talking about the hips, knees, shoulders and the spine. We know that osteoarthritis is more common in patients who are overweight and suffering from obesity and this is almost certainly purely a mechanical manifestation in that because there is more weight to carry around in the form of adipose tissue then inevitably one would expect more wear and tear on these joints.

In a normal healthy joint, there are typically two bones that articulate with each other. So as an example, the knee joint is where the femur or thigh bone joins the tibia or shinbone. A joint between the bone itself would be very destructive and therefore the surfaces where they meet are covered by a material called articular cartilage which is very smooth and is lubricated by fluid produced automatically by the joint called synovial fluid. This is effectively the body’s lubrication oil.

With osteoarthritis, there is destruction of the articular cartilage and this may happen purely as a manifestation of the weight that is being carried by the individual or possibly as a result of an injury that has happened in the past such as a fracture or a direct tear of the cartilage. This then exposes the underlying bone; and bone rubbing on bone exacerbates the inflammation and thus the symptoms enormously.

The typical symptoms of osteoarthritis affecting the major joints are limited mobility due to stiffness but also pain, typically exacerbated by exertion. The mainstay of treatment has been simple pain relief in the form of something like paracetamol but also utilising an analgesic which specifically targets the inflammatory response so something like ibuprofen.

However, there comes a point where the simple pain relief is no longer sufficient and if the symptoms restrict the individual sufficiently such that they can no longer enjoy their recreational activities or indeed carry out their occupation then a joint replacement needs to be considered.

Joint replacement surgery such as a total hip replacement or a total knee replacement as the name suggests replaces the whole joint with an artificial joint which is usually a combination of metal and plastic. Whilst this usually gives the patient back most of their mobility, it never fully replaces the real thing and of course over time the artificial joint itself will undergo wear and tear and after several years may need to be replaced again.

Clearly the aim of management of osteoarthritis needs to change from one of fixing things when they have gone wrong to preventing the problem in the first place and it is a simple matter of logic that if it is related to carrying around too much weight then we are duty bound to reduce this risk factor as far as possible.