Trigger Finger

Question 1

What is trigger finger?

Answer 1

Stenosing flexor tenosynovitis
Finger or thumb click or lock when in flexion, preventing a return to extension.
Can affect one or more tendons of the hand, mostly occurring spontaneously
Mostly idiopathic

Question 2

What usually precedes trigger finger?

Answer 2

flexor tenosynovitis (inflammation and swelling of tendon), often from repetitive movements, leading to inflammation of the tendon and sheath.
Superficial and deep flexor tendons with local tenosynovitis at the metacarpal head subsequently develop localised nodal formation on the tendon distal to the pulley.
When the fingers are flexed the node moves proximal to the pulley however when the patient attempts to extend the digit, this node fils to pass back under the pulley, rocking the digit in flexion.

Question 3

What is the function of the flexor sheath and pulley system?

Answer 3

Ensures the flexor tendons remain in the joints axis of motion and prevents bowstringing.

Question 4

What are the three types of pulley? Which pulley is most frequently involved in trigger finger?

Answer 4

Palmar aponeurosis - arises from the palmar aponeurosis and is made up of transverse fascicular bands

Annular ligaments (5 in total)- A2 and A4 prevent bowstringing. A1, A3, A5 overlie the MCP and PIP and DIP joints respectively.

Cruciate ligaments (3) - prevent collapsing and expansion of the sheath during movement of the digits.

A1 is most frequently involved in trigger finger.

Question 5

What are risk factors for trigger finger?

Answer 5

Occupation/hobby involving prolonged gripping and use of the hand
RA
DM
Female
Increasing age

Question 6

What is the clinical presentation of trigger finger?

Answer 6

Painless clicking, snapping, catching when trying to extend their finger (most commonly middle or ring finger) - more than one finger can be involved and may be bilateral.

Over time this may become painful, especially over the volar aspect of the MCP joint and digits start to lock in flexion.

Assess for clicking/pain/masses/lumps on examination

Question 7

What fingers is trigger finger most common in?

Answer 7

middle and ring

Question 8

What are differential diagnoses for trigger finger?

Answer 8

Dupuytren’s contracture - flexion is painless, fixed and cannot be passively corrected.

Acromegaly - excessive GH results in swelling of flexor synovial within tendon sheath due to increased extracellular volume limiting flexion and extension

Infection within tendon sheath - preceded with trauma and the finger becomes swollen, erythematous and tender with passive movement of digits causing pain

Genglion in tendon sheath

Question 9

Give management for trigger finger?

Answer 9

Conservative - advise on pain-causing activities
Small splint to hold the finger in extension at night

Medical - severe or non-responsive to conservative - trial steroid injection

Surgical - Percutaneous trigger finger release via a needle involving the release of the tunnel using a needly under local anaesthetic
Surgical decompression of the tendon tunnel can be trialled where roof of tunnel is slit in turn widening its mouth to release the tendon under local/general