What are the recommended imaging modalities for assessing joint pain in adults, and when should each be used?

Recommended Imaging Modalities for Assessing Joint Pain in Adults and Their Clinical Scenarios:

• Plain X-ray: First-line imaging for suspected osteoarthritis in adults aged 45 or over with activity-related joint pain and typical symptoms, but imaging is not routinely recommended for diagnosis unless atypical features or alternative diagnoses are suspected. It is also the initial investigation for suspected axial spondyloarthritis to assess sacroiliac joints unless the skeleton is immature. Diagnosis of ankylosing spondylitis can be made if X-ray shows sacroiliitis meeting modified New York criteria ¹,⁴.
• MRI: Recommended when plain X-ray is inconclusive or not appropriate, especially in suspected axial spondyloarthritis to detect early inflammatory changes (osteitis or bone marrow oedema) before structural damage is visible on X-ray. MRI is also used to assess joint inflammation and soft tissue involvement in complex or atypical cases, including suspected bone or joint tuberculosis ²,³,⁴.
• CT Scan: Used selectively for detailed bone assessment in suspected bone or joint tuberculosis or when precise anatomical detail is required, considering availability and site of disease ².
• Ultrasound: May be used for assessment of soft tissue structures, joint effusions, and guidance for aspiration or injections, and in localized tuberculous abscesses outside lymph nodes ².
• Dual-energy X-ray Absorptiometry (DXA): Not for joint pain per se but used to assess bone mineral density in patients with fragility fractures or risk factors for osteoporosis, which may contribute to joint symptoms ⁶.

Summary of Clinical Scenarios:

• Osteoarthritis: Clinical diagnosis without routine imaging unless atypical features (e.g., rapid symptom worsening, hot swollen joint) or diagnostic uncertainty; X-ray if imaging needed ¹.
• Axial spondyloarthritis: Start with X-ray of sacroiliac joints; if negative or skeleton immature, proceed to MRI for early inflammation detection ³,⁴.
• Suspected bone/joint tuberculosis: Use X-ray, CT, or MRI depending on site and availability; biopsy or aspirate for microbiological confirmation ².
• Follow-up imaging for osteoarthritis management is not routinely recommended ¹.