What is trigger finger in in rheumatoid arthritis (RA)?

Updated: Jan 11, 2019
  • Author: Michael Neumeister, MD, FRCSC, FACS; Chief Editor: Joseph A Molnar, MD, PhD, FACS  more...
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Answer

Answer

Synovial proliferation produces discrete rheumatoid nodules on tendons, which can result in trigger finger. The size and location of these nodules on the flexor tendon determine the degree of triggering.

Four types of trigger finger occur in RA. Type 1 is similar to nonrheumatoid stenosing tenosynovitis, in which the tendons catch at the first annular pulley during flexion secondary to small, localized hyperproliferation of the synovium. In type 2, the nodules form in the distal palm and cause the finger to lock in flexion. In type 3, nodules on the flexor digitorum profundus (FDP) tendon near the second annular pulley (over the proximal phalanx) lock the finger in extension. Type 4 trigger finger results from generalized tenosynovitis within the fibro-osseous canal. Active motion is more restricted than passive motion, and contracture and stiffness result.


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