Osteoarthritis – aetiology, assessment and management of a heterogeneous condition

Osteoarthritis (OA) is a common and debilitating condition worldwide. Despite the huge variety of treatment options available, many patients live with considerable ongoing pain and disability, even after surgical intervention. The mechanisms underlying structural and symptomatic disease and the relationship between the two are not entirely understood. Increasing use of more sensitive imaging such as magnetic resonance imaging (MRI) has identified further structural targets but, at present, MRI is no better than plain radiography at distinguishing between patients with and without symptomatic disease. Study of the neural processing, both centrally and peripherally mediated, is under way, with the aim of narrowing the discrepancy. The assessment of pain in cases of OA is complex with significant temporal, anatomical and qualitative variation between patients. The simple visual analogue score is not able to capture this information and so more specific techniques are being developed and applied. Similarly, the investigation of the mechanisms for pain in cases of OA has broadened, encompassing the full spectrum of methods from cellular and genetic disposition to the holistic assessment of mood and sociocultural factors. Current management strategies advise thorough assessment of patients with a biopsychosocial model in place. Appropriate therapies can then be selected from the non-pharmacological, pharmacological and surgical options available and applied in combination according to the needs of an individual patient. The identification of formal phenotypes, or clinically important subsets of patients, among this heterogeneous condition is in progress. It is anticipated that this approach will benefit the understanding the underlying aetiology as well as the impact on patient therapy.