Which deformities of the proximal interphalangeal (PIP) joint or the distal interphalangeal (DIP) joints are associated with rheumatoid arthritis (RA)?

Updated: Jun 11, 2021
  • Author: Michael Neumeister, MD, FRCSC, FACS; Chief Editor: Joseph A Molnar, MD, PhD, FACS  more...
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The swan-neck and boutonniere deformities are common in, but not unique to, patients with RA. In the swan-neck deformity, the DIP joint is flexed and the PIP joint is hyperextended. The boutonniere deformity is characterized by the opposite, with DIP joint hyperextension and PIP joint flexion. Both are caused by an imbalance of the forces on these joints due to synovial proliferation.

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