What is the medical term for thumb tendinitis, also known as De Quervain's (De Quervain's tenosynovitis)?

De Quervain's Tenosynovitis

The medical term for thumb tendinitis is De Quervain's tenosynovitis (also called De Quervain's disease or De Quervain's stenosing tenosynovitis). 1, 2, 3

Anatomical Definition

• De Quervain's tenosynovitis is a stenosing tenosynovitis of the first dorsal compartment of the wrist, affecting the abductor pollicis longus (APL) and extensor pollicis brevis (EPB) tendons within their shared fibro-osseous canal 3, 4.

• The condition involves non-inflammatory thickening of the tendinous sheath that leads to entrapment and increased friction of these tendons, rather than true inflammation 3, 5.

• Pain results from resisted gliding of the APL and EPB tendons through the first dorsal compartment during thumb and wrist movements 4.

Clinical Presentation

• Well-localized tenderness over the radial styloid at the base of the thumb on the dorsal wrist is the key diagnostic feature 2.

• Positive Finkelstein test (pain with ulnar deviation of the wrist while the thumb is flexed into the palm) confirms the diagnosis 6, 7.

• Visible swelling over the first dorsal compartment may be present 2.

• The condition is more common in women, particularly those aged 30-50 years and those 4-6 weeks postpartum 3.

Important Anatomical Consideration

• Subcompartmentalization within the first dorsal compartment can be detected by ultrasound and may affect treatment outcomes, particularly surgical management 8, 2.