Trigger Finger (Stenosing Tenosynovitis)

Trigger Finger (stenosing tenosynovitis) is catching or locking of a digit due to stenosis at the A1 pulley.

Differential Diagnosis

No imaging is required for typical trigger finger with clear clinical findings.

View larger

The injection is the first-line treatment and the topic stresses "into the sheath, not the tendon" — but it never says what actually goes wrong, and these are exactly the points to consent for.

• Subcutaneous fat atrophy and skin hypopigmentation at the injection site. Steroid that tracks into the dermis/subcutaneous fat causes a depressed, pale patch — cosmetically distressing, often slow to recover or permanent, and more conspicuous in darker skin. Warn patients, and keep the injection deep to the dermis in the sheath.
• Transient hyperglycaemia in diabetics. A single corticosteroid injection can raise blood glucose for several days — relevant both to consent and to the "inject-or-operate-first in diabetes" debate, given injection already succeeds in only roughly a third to a half of diabetics.
• Flexor tendon attenuation or rupture. Rare, but the reason the steroid goes into the sheath and not the tendon, and the reason to limit the number of injections — repeated intratendinous steroid weakens the tendon.
• Steroid flare, infection and depigmentation. A short-lived increase in pain in the first 24-48 hours is common; infection is rare with aseptic technique.

How many injections? Because recurrence reaches around half of patients at one year (Rozental), repeated injections of diminishing benefit carry cumulative cost and complication risk — most clinicians proceed to release after one or two failed injections, sooner in high-risk patients (insulin-dependent diabetes, multiple digits, young age).

A2 pulley injury causing bowstringing is a serious complication. Prevention is key - know anatomy.

The surgical steps end with "check glide" and "may need to break up adhesions", and a viva asks "what if the finger is still stiff after release?" — but the topic never explains what to do when the digit is not cured. The first move is to separate two different problems, because they have different solutions.

Why WALANT matters here: operating wide awake lets the patient actively flex and extend on the table, so residual triggering from an FDS nodule is caught and dealt with at the index operation rather than discovered at the post-operative review. And the cardinal rule still holds — the answer to persistent triggering is to address the A1 release and the FDS, never to divide the critical A2 pulley.

Return to work: Light duties immediately. Full duties 2-4 weeks.

Success Rates:

• Conservative (splint): Variable (30-40%)
• Injection: 70% (lower in diabetics - 50%)
• Surgery: 95-100%

Prognostic Factors:

Most patients do very well with injection or surgery.

Global epidemiology: Lifetime prevalence is approximately 2-3% in the general population, rising to 5-20% in people with diabetes. Peak onset is in the fifth-to-sixth decade, with a female predominance (roughly 2-6:1 across series). Trigger finger is one of the commonest reasons for elective hand surgery worldwide and is a recognised marker of impaired glucose tolerance.

Side-by-side guidance: