What causes osteoarthritis?

Osteoarthritis is the breakdown and erosion of cartilage that overlies bone within a joint. This process results in inflammation within the joint, and is often felt as pain and/or stiffness. This wear and tear within the joint is normal part of the ageing process for which no one is immune from. The onset of osteoarthritis occurs at different rates for different individuals. It seems to be more prevalent in males for those under 45 years of age, however after age 55, a greater percentage of females suffer from it. There is a genetic predisposition to osteoarthritis, but age appears to be the greatest contributing factor for it, with obesity the second greatest. The cartilage that is damaged (articular cartilage), provides some shock absorption in the joint and a low friction surface for joint movement. It appears white and shiny and is hard to touch, much like the enamel on your teeth. Articular cartilage is smooth in situations where no osteoarthritis is present and becomes frayed and motley when wear and tear has eroded it. Articular cartilage is stressed by normal movements and activities, and gradually wears away with time. High stress activities are thought to increase the likelihood of damage, although this has not been clearly proven with research. It also has an inefficient blood supply, meaning that after damage, there is little to no re-growth or healing that can occur. This makes osteoarthritis largely irreversible with current medical techniques.

Areas of high stress, high wear or injury can accelerate this process of wearing and may lead to earlier onset of these arthritic changes. If you are worried that your joints may be susceptible to osteoarthritis we recommend an assessment of your muscle strength as well as your biomechanics around the joint in question. For lots of situations where osteoarthritis is developing there are ways to slow its progression and prolong the onset of pain, stiffness and limited function. It has been proven that one of the best ways to minimise the progression of arthritic changes is strengthening of the muscles around the susceptible joint. This enhances the muscles capacity to absorb load, creating less stress on the joint. An assessment will also look at the biomechanical loads around the joint, this may include looking at feet position, footwear and each of the major muscles contribution to movement. Imbalanced biomechanics can increase the load on small areas in the joint wearing these surfaces out more quickly.

Written by Mark Fotheringham (Physiotherapist)

Published November 7, 2012