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Trigger Finger | Stenosing Tenosynovitis

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Trigger Finger | Stenosing Tenosynovitis

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Trigger Finger (or Stenosing tenosynovitis) is an inflammatory condition that narrowing the retinacular sheath of the tendon, and therefor leads to an entrapment of the tendon at A1 pulley.

Trigger finger is more common in women older than age 50, and it’s most commonly occur in ring and middle fingers. The incidence of trigger digits is 2.2% in nondiabetic adults older than 30 years and up to 10% in patients with insulin dependent diabetes mellitus.

It’s commonly associated with diabetes and inflammatory arthropathy, and may result from repetitive grasping activities.

See Also: Hand Anatomy


The phenomenon of trigger finger is due to mechanical impingement of the digital flexor tendons as they pass through a narrowed retinacular pulley (A1 Pulley) at the level of the metacarpal head.

The most remarkable pathologic changes are seen in the pulley itself, which demonstrates gross hypertrophy, described as a “whitish, cicatricial collar-like thickening.”

A1 pulley and the corresponding surface of the flexor tendon undergo fibrocartilaginous metaplasia under the influence of repetitive, compressive loads.

Microscopic examination of A1 pulley demonstrates the following changes:

  1. Degeneration,
  2. Cyst formation,
  3. Fiber splitting,
  4. Lymphocytic or plasma cell infiltration,
  5. Presence of chondrocytes,
  6. Presence of type III collagen.

Related Anatomy

Every digit (except the thumb) has:

  1. 5 annular pulleys (A1 to A5).
  2. 3 cruciate pulleys (C1 to C3).
finger pulley

While the thumb has:

  1. 2 annular pulley.
  2. An oblique pulley .

A1 Pulley is where trigger finger occurs.

A2 and A4 are the most important pulleys to prevent flexor tendon bow-stringing.

See Also: Extensor compartments of the wrist
thumb pulleys


The Classification of Trigger Finger was proposed by Quinnell and modified by David Green in 1997.

Grade I (pre-triggering)Pain.
History of catching, but not demonstrable on physical examination; tenderness over the A1 pulley.
Grade II (active)Demonstrable catching, but the patient can actively extend the digit.
Grade III (passive)Grade IIIA: Demonstrable catching requiring passive extension.
Grade IIIB: inability to actively flex.
Grade IV (contracture)Demonstrable catching with a fixed flexion contracture of the PIP joint.
Green Classification of Trigger Finger – From Greens Operative Hand Surgery 7th ed.
See Also: Classification of Nerve Injuries

Clinical Evaluation

  1. Pain / tenderness in the distal palm.
  2. Progresses to mechanical catching/locking.
  3. The finger may become in fixed flexion.
  4. Patients often complain of referred pain at the dorsal MCP/PIP area.

Trigger Finger Treatment

Non-Operative Treatment

Indicated as a first line of Trigger Finger treatment and includes:

  1. Splinting
  2. Activity modification
  4. Steroid injections:

Steroid injection is curative in about 60% of patients.

Diabetic patients generally less responsive to steroid injection.

Rarely, tendon ruptures have been reported after corticosteroid injection, so intratendinous injection should be avoided given the known attritional effects of corticosteroids on collagen.

See Also: Flexor Tendon Injury of the Hand
trigger finger injection

Operative Treatment

Trigger finger surgery release is indicated after failure of nonoperative management. Surgical release of A1 pulley (open or percutaneous) with resection of ulnar FDS slip when necessary.

trigger finger surgical treatment
trigger finger release
Percutaneous release of trigger finger
Percutaneous release of trigger finger

Congenital Trigger Thumb

Congenital Trigger Thumb is the most common cause of abnormal thumb posturing in flexion or extension in children. The condition has a bilateral incidence of 25% to 33%.

Pathologic specimens document more frequent thickening and synovial proliferative changes in the tendon itself rather than in the annular sheath.

Notta node is a pathologic nodular thickening in the tendon: It can be palpated just proximal to the proximal border of the A1 pulley, confirming the diagnosis.


Congenital Trigger Thumb may initially be observed. In case of observation failure, annular pulley release may be required between ages of 2 and 4 to prevent IP joint contracture.

Trigger Finger in Childhood

It’s usually caused by anatomic anomaly. Children with storage diseases, such as Hurler syndrome, can acquire trigger finger and carpal tunnel syndrome as a result of abnormal collections of mucopolysaccharide within and around the flexor tendons. A1 pulley release may not resolve triggering; additional A3 release or resection of ulnar FDS slip may be required.

References & More

  1. Campbel’s Operative Orthopaedics 12th edition Book.
  2. Millers Review of Orthopaedics -7th Edition Book.
  3. Dutton’s Orthopaedic Examination, Evaluation, And Intervention 3rd Edition.
  4. Jeanmonod R, Harberger S, Waseem M. Trigger Finger. [Updated 2021 Nov 7]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2022 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK459310/
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