How does rheumatoid arthritis (RA) affect the ankles and feet?

Updated: Feb 07, 2020
  • Author: Howard R Smith, MD; Chief Editor: Herbert S Diamond, MD  more...
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The ankle joint itself is rarely involved without midfoot or MTP involvement. Because it is a mortise joint, it does not often deform. Major structural changes occur in the midfoot and foot as a result of the combination of chronic synovitis and weight bearing. Posterior tibialis tendon involvement or rupture may lead to subtalar subluxation, which results in eversion and migration of the talus laterally. Midfoot disease leads to loss of normal arch contour with flattening of the feet.

The MTP joints are inflamed in most patients and, because of the heavy loads they bear, often become deformed over time. The great toe typically develops hallux valgus (a bunion); subluxation of the phalanx at the MTP joint of the other toes predominantly occurs dorsally. Toes may exhibit compensatory flexion due to a fixed length of the flexor tendons—so-called hammer toes. The second and third metatarsal heads commonly protrude and may become the primary weight-bearing surface at the MTP joints. Calluses and pain upon weight bearing result.

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