Curriculum · Musculoskeletal / Orthopedic / Rheumatology
Trigger finger (stenosing tenosynovitis)
What it is
Trigger finger is the stenosing subtype of tenosynovitis, that is inflammation of a tendon, tendinitis, together with its synovial sheath, synovitis. The tendons of the hand and wrist, and of the fingers, are the ones most commonly affected.
Causes and risk
Non-infectious tenosynovitis is the most common form. It follows overuse tendinitis, with repetitive use of the involved tendon in texting, typing or gaming, or systemic diseases such as rheumatoid arthritis, sarcoidosis and diabetes mellitus. Infectious tenosynovitis arises by two routes. One is direct inoculation following penetrating trauma, from animal or human bites, IV drug use or thorn prick injuries. The other is hematogenous spread of infection, with Neisseria gonorrhoeae and Mycobacterium tuberculosis given as the organisms.
How it presents
Difficulty in grasping things, with pain on thumb extension and abduction, is the presentation given for tenosynovitis. The first sign is pain on passive extension of the affected tendon, and the affected fingers sit slightly flexed at rest. Swelling and palpable crepitation follow, and fever and erythema in the case of bacterial infections. Later there is tenderness along the affected tendon, and a sharp, stabbing pain worsened by activity that settles into a constant dull ache at rest.