Prospective Longitudinal Effects of Intra-articular Corticosteroid Injection on Synovial Fluid Oxygen

Inclusion criteria

• Participant is willing and able to give informed consent for participation in the study.
• Male or Female, aged 18 years or above.
• Fulfil American College of Rheumatology/European League Against Rheumatism criteria (ACR/EULAR) 2010 Rheumatoid Arthritis Classification Criteria or fulfil Classification Criteria for Psoriatic Arthritis 2006 (CASPAR).
• Participant has been selected for intra-articular corticosteroid injection as part of their routine clinical care.
• Selected joint for biopsy must be minimum Grade 2 synovial thickening for large joint (knee) and medium joint (wrist), or minimum Grade 3 synovial thickening for small joint (metacarpophalangeal).

Exclusion criteria

• Current enrolment in any other clinical study involving an investigational study treatment.
• Intramuscular, intravenous or intra-articular administration of corticosteroid within 4 weeks prior to baseline visit.
• Oral corticosteroid > 10 mg/day prednisolone or equivalent within 4 weeks prior to baseline visit.
• Oral corticosteroid dose not stable for at least 4 weeks prior to baseline visit.
• Oral non-steroidal anti-inflammatory drugs (including aspirin > 75 mg/ day and selective-cyclooxygenase inhibitors) dose not stable for at least 4 weeks prior to baseline visit.
• Disease modifying anti-rheumatic drugs (DMARDs) dose not stable for at least 4 weeks prior to baseline visit.
• History of septic arthritis.
• Participants on warfarin, heparin, low molecular weight heparin, direct oral anticoagulants. Oral anti-platelet agents are permitted.
• History of haemophilia.