MANUAL MINORS
Trigger thumb is a form of stenosing tenosynovitis that affects the flexor tendon of the thumb, causing the digit to become stuck in a flexed position and straighten with a snap. It occurs when the sheath surrounding the tendon becomes inflamed or narrowed, restricting the smooth gliding of the tendon.
This condition may result from repetitive movements, trauma, or underlying conditions such as diabetes or rheumatoid arthritis.
Diagnosis
The diagnosis is clinical and characterised by:
Clicking or locking of the thumb, particularly when attempting to extend it.
Pain and tenderness at the base of the thumb, in the tendon sheath at the A1 pulley.
A nodule may sometimes be felt at the base of the thumb.
In severe cases, the thumb may become locked in a flexed position and require manual assistance to straighten.
Differential Diagnosis
Condition | Key Differences |
|---|---|
De Quervain’s Tenosynovitis | Affects the tendons in the wrist, with pain on the radial side, without thumb locking. |
First Metacarpal Fracture | Localised pain with an inability to move the thumb, without clicking or locking. |
Carpometacarpal Arthritis | Chronic pain at the base of the thumb without sudden locking, associated with joint wear and tear. |
Flexor Tendon Rupture | Inability to actively flex the thumb, without clicking or locking. |
Emergency Management
Immobilisation of the affected thumb with a splint to reduce inflammation and prevent overuse.
Administration of non-steroidal anti-inflammatory drugs (NSAIDs) to control pain and inflammation.
Application of ice to the affected area.
Corticosteroid injections into the tendon sheath may be considered in more severe or persistent cases to reduce inflammation.
Definitive Treatment
Conservative treatment includes rest, immobilisation, and in recurrent cases, corticosteroid injections. If symptoms persist or worsen, surgery to release the A1 pulley may be necessary. This procedure involves freeing the tendon sheath to allow smooth movement without locking. Post-surgery, rehabilitation with physiotherapy is recommended to restore mobility and prevent stiffness.
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