A 55-year-old woman with long-standing rheumatoid arthritis presents with severe wrist pain, dorsal wrist synovitis, and extensor tendon rupture affecting ring and little fingers sequentially (Vaughan-Jackson syndrome). The primary pathological process causing the tendon ruptures is:

• A Hypermobility of the radiocarpal joint causing tendon fraying
• B Attrition rupture of extensor tendons over the eroded ulnar head (caput ulnae syndrome) ✓
• C Compressive neuropathy of the posterior interosseous nerve
• D Vasculitis affecting the intratendinous vessels

Explanation

Vaughan-Jackson syndrome describes sequential extensor tendon rupture in rheumatoid arthritis, starting from the ulnar side (EDM, then EDC of ring, then middle finger). It is caused by attrition rupture of the extensor tendons over the sharp, dorsally subluxed, and eroded ulnar head — the 'caput ulnae syndrome'. Synovial hypertrophy fills the extensor compartment and the irregular bone acts like a saw blade on the overlying tendons. Treatment requires Darrach procedure (distal ulnar resection) or Sauvé-Kapandji procedure combined with tendon reconstruction.

Reference: Maheshwari Essential Orthopaedics, 6th ed.

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Written and medically reviewed by the StethoPrep medical team.