fMRI and Central Sensitization in Chronic Knee Osteoarthritis. A Pre and Post TKR Study

Predicting Chronic Post TKR Pain by Assessing Central Sensitisation Using Functional Brain MRI

Painful osteoarthritis (OA) is the 4th largest cause of disability in the UK. Preoperative temporal summation, a measure of central pain facilitation, has been shown to predict postoperative pain after total knee replacement surgery (TKR). The assessment of the brain's response to noxious stimuli using non-invasive functional MRI (fMRI) may be key in identifying imaging biomarkers within the brain that map central sensitization changes seen in OA. fMRI may help explain why up to 20% of patients undergoing TKR surgery develop persistent post-operative pain. To test these concepts the study aims to functionally characterise the brain activity related to temporal summation of pain in healthy individuals and OA patients using a novel fMRI cuff algometer. Assessment of outcomes in terms of pain and function will be performed 6 months post TKR surgery

Inclusion Criteria:

• OA Group

Unilateral Knee OA No previous knee surgery Able to give informed consent Age > 40 years

- Healthy Volunteers Group

No OA or knee pain Able to give informed consent Age > 40 years

Exclusion Criteria:

-OA Group

Major medical, psychiatric, neurological Cx Other chronic pain condition (fibromyalgia) Contraindications to MRI Active Cancer Neuropathic drug treatment

-Healthy Volunteers Group

Pregnancy Lower limb pain or previous knee surgery Contraindications to MRI Active Cancer Major medical, psychiatric, neurological condition