Which deformities are commonly associated with rheumatoid arthritis?

• A. Boutonniere deformity and Swan neck deformity with MCP ulnar subluxation
• B. Heberden's nodes
• C. Dupuytren contracture
• D. Carpal tunnel syndrome

Answer: (A)

Rheumatoid arthritis causes chronic inflammation of the joints in the hands, leading to weakening and rupture of ligaments and tendons around the fingers. This produces the characteristic deformities you see with advanced RA: swan neck deformity, where the PIP joint stays hyperextended while the DIP joint flexes; boutonniere deformity, where the PIP is flexed and the DIP is extended due to disruption of the extensor mechanism; and MCP joints often drift ulnarly with subluxation, giving fingers a tendency to move toward the little finger. Together, these changes describe the RA hand pattern most commonly seen, including the combination of boutonniere and swan neck deformities with MCP ulnar subluxation.

Heberden's nodes are from osteoarthritis, not RA. Dupuytren contracture involves the palmar fascia and is not a typical RA deformity. Carpal tunnel syndrome can occur with RA due to inflammation, but it is not a deformity of the fingers and hands in the same way, so it’s not the classic RA hand deformity.