Inflammatory SI Joint Pain (Sacroiliitis) vs Mechanical: Key Clues

Discover how to recognize sacroiliitis, its causes, imaging signs, and key mimics to improve diagnosis and patient care. In this video we define sacroiliitis, explain primary causes like axial spondyloarthritis (including ankylosing spondylitis), psoriatic arthritis, IBD-related spondyloarthritis, and reactive arthritis, and show how inflammatory back pain presents (insidious onset, night pain, morning stiffness, improves with exercise). Learn the New York radiographic grading (0–4) and why pelvic x-rays can miss early disease—MRI with STIR or fat-suppressed T2 is preferred for detecting bone marrow edema and early erosions, while CT shows structural damage and bone scan is less specific.

You’ll gain practical guidance on interpreting imaging: bilateral symmetrical changes suggest ankylosing spondylitis; non-radiographic axial spondyloarthritis may only appear on MRI; and normal x-rays don’t rule out early sacroiliitis. The video highlights important mimics—secondary hyperparathyroidism, mechanical stress/degenerative change, insufficiency fractures (Honda sign), osteitis condensans ilii, postpartum bone marrow edema, and septic sacroiliitis—detailing their distinguishing imaging patterns and clinical clues. Understand anatomical load-bearing zones versus inflammatory locations to differentiate mechanical from inflammatory marrow changes.

Clinically focused and image-driven, this concise walkthrough equips clinicians and trainees with the knowledge to spot sacroiliitis, choose the right imaging, and avoid common diagnostic pitfalls. Watch to sharpen diagnostic accuracy and learn when to refer for MRI or specialist assessment for optimal patient outcomes.