A 28-year-old woman presents with chronic hip pain and radiograph shows erosion of the acetabulum and femoral head with reduced joint space. 'Wandering acetabulum' sign is present. This is characteristic of:

• A Osteoarthritis of the hip with secondary acetabular protrusion
• B Tuberculous arthritis of the hip (morbus coxae senilis pattern) ✓
• C Charcot's neuropathic arthropathy
• D Avascular necrosis of the femoral head with secondary arthritis

Explanation

TB of the hip joint (coxitis) classically produces the 'wandering acetabulum' sign — progressive erosion of the acetabular roof and medial migration of the femoral head as bone destruction progresses. The Phemister triad (osteoporosis, peripheral erosions, gradual joint space narrowing) is characteristic. Osteoarthritis causes joint space narrowing but with osteophyte formation rather than erosive destruction. AVN produces subchondral collapse with maintained acetabular architecture early. Charcot arthropathy shows gross disorganisation and bone fragmentation.

Reference: Maheshwari Essential Orthopaedics, 6th ed.

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Written and medically reviewed by the StethoPrep medical team.