Osteoarthritis is the most common form of arthritis and one of the most frequent causes of musculoskeletal pain. Traditionally, the pain has been considered to be nociceptive, which means that it usually resolves with the removal of whatever is provoking it. Recent evidence supports the additional contribution of central sensitisation.
Transcutaneous electrical stimulation can reduce pain in people with osteoarthritis
Central sensitisation involves changes in central neurons that regulate pain perception. It is a process by which repeated administration of a stimulus results in the progressive amplification of response. Central sensitisation is a chronic condition, related to inflammation or mechanical damage and causes pain even at rest as well as hypersensitivity and dysaethesias, or burning and crawling sensations. It is not easy to diagnose but is often suspected if there is a discrepancy between pain severity and radiological features of osteoarthritis.
The association between osteoarthritis and central sensitisation is emerging so there is no specific guidance on its management. Treatment is challenging because response to conventional analgesics is limited. Non-pharmacological approaches include cognitive behaviour therapy, transcutaneous electrical stimulation and transcranial magnetic stimulation. Drug treatments could include those increasing levels of neurotransmitters such as serotonin, norepinephrine and gamma-Aminobutyric acid.
Further research is needed to determine the best approach in clinical practice but clinicians should be aware of the possibility of central sensitisation in patients presenting with severe pain with unusual features.