A 50-year-<>ld woman with a 20-year history of rheumatoid arthritis in both hands suddenly develops finger drop of the ring fmger of her right hand.
Which deformity is most likely to have caused this complication?
Fixed hyperextension (swan·n~k deformity) of the proximal interphalangeal joint
Ulnar deviation at the metacarpophalangeal joints
C Boutonniere deformity
Swelling and dorsal subluxation of the ulnar styloid
E Squared hand and fixed adduction of the thumb
Hand deformities in rheumatoid arthritis
Swelling and dorsal subluxation of the ulnar styloid leads to wrist pain and may cause rupture of the fmger extensor tendons. This causes f1nger drop of the little and ring f1ngers predominantly, which needs urgent surgical repair. Swan·n~k and Boutonniere deformities and ulnar deviation at the metacarpophalangeal joints occur in rheumatoid arthritis, but do not cause fmger drop.
The squared hand is seen in severe nodal osteoarthritis and is caused by bony swelling of the carpometacarpal joint and f1xed adduction of the thumb.