Trigger Finger & de Quervain

Trigger finger (stenosing tenosynovitis) is caused by a size mismatch between the flexor tendon and the first annular (A1) pulley at the level of the metacarpal head. Thickening and narrowing of the A1 pulley (or, less commonly, enlargement of the flexor tendon itself — particularly the FDS/FDP junction nodule) prevents smooth tendon gliding, causing catching, clicking, and ultimately locking of the finger in flexion or extension. It is one of the most common hand conditions presenting to orthopaedic and hand surgery clinics.

• Epidemiology: lifetime incidence approximately 2–3%; female predominance; peak incidence 5th–6th decade; the ring finger is the most commonly affected digit, followed by the thumb (trigger thumb), middle finger, little finger, and index finger; bilateral in 10%; associated with diabetes (multiple trigger fingers are common — diffuse tenosynovitis), rheumatoid arthritis, hypothyroidism, amyloidosis, and carpal tunnel syndrome (up to 60% of patients with CTS have coexisting trigger finger)
• Anatomy: the A1 pulley lies at the level of the MCP joint (palmar aspect); it is the first of the five annular pulleys of the finger; it originates from the volar plate and the palmar fascia; the A2 and A4 pulleys are the critical pulleys for biomechanical finger function — they must NEVER be divided; the A1 pulley can be safely divided without biomechanical consequence (no bowstringing)
• Notta`s node: the palpable tender nodule on the palmar aspect of the MCP joint representing the thickened tendon or fibrous nodule that catches against the A1 pulley; its presence is highly characteristic of trigger finger

• Quinnell grading: Grade 0 — unaffected; Grade 1 — uneven movement (catching without locking); Grade 2 — actively correctable (the finger locks in flexion but the patient can actively extend it with effort); Grade 3 — passively correctable (locked in flexion; requires passive correction by the other hand); Grade 4 — fixed flexion deformity (cannot be corrected passively); Grades 1–2 may respond to conservative treatment; Grades 3–4 require intervention
• History: catching or clicking with finger flexion/extension; finger locking (usually in flexion — the FDP and FDS can pull the finger into flexion but cannot overcome the A1 pulley resistance to extend); morning stiffness (the finger is worst in the morning, improving with activity — due to reduced tendon fluid at rest); pain at the A1 pulley (palmar MCP crease); the patient may release the locked finger with a `pop` using the other hand
• Examination: palpable tender nodule at the A1 pulley (Notta`s node); catching or locking on active flexion-extension; passively correct the locked finger; assess for associated conditions (carpal tunnel syndrome, Dupuytren`s, diabetes, RA)

• Splinting: extension splint to the MCP joint (at 0–15° extension) prevents the triggering position; useful for Grade 1–2; compliance-limited; success rate approximately 55–70% for Grade 1–2
• Corticosteroid injection into the tendon sheath at the A1 pulley: the most effective non-operative treatment; a mixture of corticosteroid (triamcinolone or methylprednisolone) and local anaesthetic is injected into the tendon sheath at the A1 pulley level (palmar surface, distal to the web crease at the MCP joint); the injection reduces the inflammatory component of tendon sheath thickening; success rate approximately 70–90% for a single injection; a second injection is offered if the first partially resolves symptoms; a third injection has diminishing returns; lower success rates in diabetics, longstanding disease, and Grade 3–4; associated with temporary glucose elevation in diabetics — warn patients
• USS-guided injection: more accurate placement into the tendon sheath (vs palpation-guided); evidence shows modestly higher success rates with USS guidance; recommended for difficult cases or recurrent disease after failed injection
• Surgical A1 pulley release: definitive treatment; the A1 pulley is divided through a transverse palmar incision under local anaesthetic (WALANT — wide awake local anaesthesia no tourniquet is increasingly used); the patient can actively flex and extend the finger intraoperatively to confirm complete release; the neurovascular bundles must be identified and protected (they lie on either side of the A1 pulley and are particularly vulnerable at the thumb and index finger levels); success rate >95%; the A1 pulley heals but leaves a wider channel — permanent relief; the A2 pulley must NOT be divided
• Percutaneous A1 pulley release: a needle (21G) is used percutaneously to divide the A1 pulley without an open incision; performed under local anaesthetic; comparable success rates to open release; slightly higher risk of incomplete release and neurovascular injury (particularly at the thumb — where the digital nerve is very close to the A1 pulley); popular in experienced hands

de Quervain tenosynovitis is a stenosing tenosynovitis of the first dorsal extensor compartment of the wrist, affecting the abductor pollicis longus (APL) and extensor pollicis brevis (EPB) tendons. It is characterised by pain and tenderness at the radial styloid process, aggravated by thumb and wrist motion. It is the most common tendon entrapment at the wrist and disproportionately affects new mothers (handling of infants), typists, and racket sport players.

• Epidemiology: female:male ratio approximately 8–10:1; peak incidence 30–50 years; strongly associated with pregnancy and the postpartum period (new mothers) due to repetitive wrist and thumb loading with infant care; also associated with manual work and racket sports
• Anatomy: the first dorsal extensor compartment is a fibro-osseous tunnel on the radial side of the wrist, just distal to the radial styloid; it normally contains the APL and EPB tendons; in approximately 30% of individuals, there is a septum dividing the compartment into two sub-compartments (the EPB is in its own separate sub-tunnel); this anatomical variant is important surgically — if the EPB sub-tunnel is not released, the EPB continues to be entrapped and symptoms persist after surgery
• Pathology: stenosing tenosynovitis — the first dorsal compartment becomes thickened, fibrotic, and stenotic; the tendons glide poorly within the narrowed compartment; histologically: fibrocartilaginous metaplasia of the retinaculum; not a primarily inflammatory condition (similar to trigger finger — degeneration, not inflammation)

• History: radial-sided wrist and thumb pain; pain with pinch grip, lifting, turning taps and door handles, carrying bags, picking up infants; swelling at the radial styloid; occasionally a palpable thickening over the first compartment
• Finkelstein test: the most sensitive clinical test for de Quervain; the patient flexes the thumb into the palm and closes the fingers over it (making a fist with the thumb inside); the examiner then ulnar-deviates the wrist; positive if pain is reproduced over the first dorsal compartment (radial styloid area); sensitivity approximately 89%; the Eichhoff test is often incorrectly called the Finkelstein test — the true Finkelstein test involves the examiner grasping and pulling the thumb rather than the patient tucking it; both are commonly positive in de Quervain; compare with the contralateral wrist as false positives occur in CMC joint arthritis and intersection syndrome
• Investigations: clinical diagnosis; X-ray to exclude CMC joint OA (first CMC OA can mimic de Quervain); USS confirms tendon sheath thickening and may show a septum in the first compartment (pre-operative planning); MRI rarely required
• Differential diagnosis: first CMC joint OA (the `grind test` — axial compression + rotation of the thumb MCP reproduces pain at the CMC joint); intersection syndrome (pain and crepitus 4–6 cm proximal to the wrist at the crossing point of the first and second compartment tendons — `squeaking`); Wartenberg`s syndrome (entrapment of the superficial radial nerve — burning/tingling rather than mechanical pain)

• Non-operative: rest; thumb spica splint (immobilises the first compartment); NSAIDs; activity modification
• Corticosteroid injection into the first dorsal compartment: the most effective non-operative treatment; the injection must be placed into the tendon sheath (not the tendon); success rate approximately 70–80% for a single injection; patients with a separate EPB sub-compartment may require injection of both sub-compartments; USS guidance increases accuracy (identifies the septum and allows injection of each sub-tunnel separately); two injections are offered before considering surgery
• Surgical first compartment release: indicated after failure of ≥2 steroid injections; through a transverse or oblique incision over the radial styloid; the first dorsal compartment retinaculum is divided longitudinally; CRITICAL — the EPB sub-tunnel (if present) MUST be identified and released separately; failure to release the EPB sub-tunnel is the most common cause of failed de Quervain surgery; the superficial radial nerve branches must be identified and protected to prevent painful neuroma formation
• Complications of surgery: superficial radial nerve injury or neuroma (the most feared complication — produces chronic pain and dysaesthesia over the dorsoradial thumb and hand); scar tenderness; EPB sub-tunnel not released (persistent symptoms); subluxation of the APL tendon (if the retinaculum is over-released)

• Trigger finger: stenosing tenosynovitis at A1 pulley; ring finger most common; Quinnell Grade 1–4; Notta`s node = palpable tendon nodule at A1 pulley level
• A1 pulley: safe to divide; A2 and A4 pulleys are critical for flexor function — NEVER divide; bowstringing if A2 or A4 divided
• Steroid injection: 70–90% success rate; first line after splinting fails; lower success in diabetes, Grade 3–4, longstanding disease; warn diabetics about temporary glucose rise
• WALANT surgery: wide awake local anaesthesia no tourniquet; patient actively moves finger intraoperatively to confirm complete A1 pulley release; increasing standard of care
• de Quervain: first dorsal compartment (APL + EPB); radial styloid pain; new mothers; Finkelstein test positive (pain on ulnar deviation with thumb in fist)
• EPB sub-compartment (30% of individuals): separate septum in first compartment; MUST be released surgically; most common cause of failed surgery = EPB sub-tunnel not released
• Steroid injection for de Quervain: 70–80% success; USS-guided injection into each sub-compartment if septum present; two injections before surgery
• Superficial radial nerve: must be identified and protected in de Quervain surgery; injury causes neuroma + chronic dorsoradial hand pain; most feared surgical complication
• First CMC OA vs de Quervain: OA — CMC grind test positive; pain at CMC joint base of thumb; X-ray shows CMC OA; de Quervain — Finkelstein positive; tenderness at radial styloid/first compartment
• Intersection syndrome: APL/EPB cross the second compartment (ECRL/ECRB) 4–6 cm proximal to the wrist; crepitus + swelling at this crossing point; not de Quervain; responds to splinting + injection