What causes trigger finger (TF)?

Updated: Apr 26, 2021
  • Author: Satishchandra Kale, MD, MBBS, MBA, MCh(Orth), FRCS(Edin), FRCS(Tr&Orth); Chief Editor: Harris Gellman, MD  more...
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Answer

The etiology of TF is unknown or uncertain. It is suspected that nodule formation in the tendon, morphologic changes in the pulley, or both in combination may effect triggering, though why these changes are actually initiated remains unknown.

Several studies have demonstrated a correlation between TF and activities that require exertion of pressure in the palm while a powerful grip is used or that involve repetitive, forceful digital flexion (eg, arc welding, use of heavy shears). Proximal phalangeal flexion in power-grip activities causes high annular loads at the distal edge of the A1 pulley. Hueston and Wilson have suggested that bunching of the interwoven tendon fibers causes the reactive intratendinous nodule observed at surgery. [19]

Thus, in conclusion, the exact etiology remains unknown, but certain conditions such as diabetes mellitus (DM) or rheumatoid arthritis (RA) may predispose an individual to triggering of the digit.

Sampson et al concluded that the underlying pathobiologic mechanism for triggering is fibrocartilaginous metaplasia of the pulleys due to trauma or disease. [20] Several studies have failed to demonstrate the presence of acute or chronic inflammatory cells within the tenosynovium. The suffix -itis in the term stenosing tendovaginitis actually is a misnomer unless the condition is associated with RA or inflammatory arthritis.


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