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TRIGGER THUMB PEDIATRIC

Introduction

Pediatric trigger thumb is characterized by interphalangeal (IP) joint contracture and the presence of a flexor tendon nodule at the metacarpal head (Notta’s node). The pathophysiology is stenosing tenosynovitis of the flexor pollicis longus (FPL) tendon. There is ongoing debate as to whether the condition is present at birth or develops early postnatally. Results from numerous observational studies support the latter assertion.1-6

Related Anatomy

  • Thumb IP joint
  • Thumb metacarpal head
  • FPL tendon

Pathophysiology

  • Abnormal collagen degeneration and synovial proliferation cause the FPL tendon to thicken relative to the A1 pulley, and this disrupts normal tendon gliding.

Incidence and Related Conditions

  • Pediatric trigger thumb is a separate entity from adult, acquired trigger thumb.
  • Incidence has been estimated to be 3.3 cases per 1000 live births;3 boys and girls are affected equally; ~25% of cases are bilateral.
  • Pediatric trigger thumb has been associated with trisomy-13 syndrome, polydactyly of other digits, triphalangeal thumbs, broad thumbs, retroflexible thumbs, radial ray defects, syndactyly and clenched hand syndrome, among others.

Differential Diagnosis

  • Congenital Hypoplastic Thumb Extensors
  • Thumb fracture
  • Thumb dislocation
  • Congenital absence of extensor tendon
  • Arthrogryposis
Clinical Presentation Photos and Related Diagrams
  • Pediatric Trigger Thumb (Formerly Congenital Trigger Thumb)
    Pediatric Trigger Thumb (Formerly Congenital Trigger Thumb)
Symptoms
Lump or nodule under first flexion crease of the thumb (Notta’s Nodule)
Limited painful passive thumb range of motion
Flexion contracture of the joint (IP joint) at the tip of the thumb
Painful clicking, snapping, catching, triggering or temporary locking of thumb with motion
Pain near the base of the thumb on palm side of the MP joint
When not being examined usually painless because child doesn't move thumb
Typical History

A three year old male child presents with a right flexed thumb IP joint and a lump on the palm side of the thumb MP joint. The child can not straighten the thumb. The mother notes that a few weeks ago the thumb would straigthen but when it did extend the thumb would "click" and  the child would occassionally cry and complain that the thumb hurt.

Positive Tests, Exams or Signs
Pediatric Trigger Thumb (Congenital)
Extensor Tendon Exam
Flexor Tendon Exam
Muscle Test and Tendon Exam: Extensor Pollicis Longus (EPL)
Muscle Test and Tendon Exam: Flexor Pollicis Longus (FPL)
Notta's Node
Tenderness
Tenderness A-1 Pulley & Triggering
Range of Motion: Active
Range of Motion: Passive
Work-up Options
Radiology studies - X-ray
Images (X-Ray, MRI, etc.)
  • Normal Pediatric Thumb. Note open growth plates at arrows.
    Normal Pediatric Thumb. Note open growth plates at arrows.
Treatment Options
Conservative: 
  • First-line options: passive extension exercises and observation
  • Extension splinting: as adjunct to extension exercise regimen; IP joint hyperextension for 6–12 weeks
Operative: 
  • Indications: should be considered if not spontaneously resolved by 12 months of age; conduct surgery between ages 2 and 3 years
  • Open A1 pulley release
Complications
  • Digital nerve injury, wound complications (scar contracture, abscess, infection), IP flexion deficit, bow-stringing of flexor tendon
Outcomes
  • Spontaneous resolution: in one study, 75% of cases resolved after 5 years of follow-up.7 In general, 30–60% of cases will resolve spontaneously before 12 months of age; <10% will resolve spontaneously after 12 months.
  • Extension splinting: 50–60% resolution in all age groups; high drop-out rate
  • A1 pulley release: 65–95% resolution in all age groups
Video
Pediatric Trigger Thumb after surgical release
Pediatric Trigger Thumb: Child demonstrating catching to his mother.
Key Educational Points
  • Congenital trigger thumbs are not congenital and they do not necessarily trigger.
  • Several exhaustive studies of newborn infants have found no cases of trigger thumb present at birth.
  • The condition usually develops between one and three years of age and presents as a flexion deformity without antecedent triggering
  • The results of surgical treatment are uniformly excellent, and tenovaginotomy is thus considered the
    most effective and conservative treatment option.
  • Extension splinting is ineffective and tedious.
  • Steroid injection is helpful only in the adult population.
  • Percutaneous tenovaginotomy has not been used in treatment of this condition and is dangerous at any time in the thumb.
Practice and CME
References

Cited

  1. Rodgers WB, Waters PM. Incidence of trigger digits in newborns. J Hand Surg Am 1994;19(3):364-8. PMID: 8056959
  2. Slakey JB, Hennrikus WL. Acquired thumb flexion contracture in children. Congenital trigger thumb. J Bone Joint Surg Br 1996;78:481-3. PMID: 8636191
  3. Kikuchi N, Ogino T. Incidence and development of trigger thumb in children. J Hand Surg Am 2006;31(4):541-3. PMID: 16632044
  4. Goldfarb CA. Congenital hand differences. J Hand Surg Am 2009;34(7):1351-6. PMID: 19700077
  5. Ruland RT, Slakey JB. Acquired trigger thumb vs. congenital clasped thumb: recognize the difference: a case report. Hand (NY) 2012;7(2):191-3. PMID: 23730240
  6. Moon WN, Suh SW, Kim IC. Trigger digits in children. J Hand Surg Br 2001 Feb;26(1):11-2. PMID: 11162006
  7. Baek GH, Lee HJ. The natural history of pediatric trigger thumb: A study with a minimum of five years follow-up. Clin Orthop Surg 2011;3:157-60. PMID: 21629478

New Articles

  1. Wilkerson JA, Strauch RJ. A simple technique for confirmation of complete release in surgical treatment of pediatric trigger thumb. J Hand Surg Am 2014;39(11):2348-9. PMID: 25442753
  2. Fawdington RA, Roberts AP. Avoiding digital nerve injury in paediatric trigger thumb release. Ann R Coll Surg Engl 2014;96(8):632. PMID: 25350202

Reviews

  1. Shah AS, Bae DS. Management of pediatric trigger thumb and trigger finger. J Am Acad Orthop Surg 2012;20(4):206-13. PMID: 22474090
  2. Ty JM, James MA. Failure of differentiation: Part II (arthrogryposis, camptodactyly, clinodactyly, madelung deformity, trigger finger, and trigger thumb). Hand Clin 2009;25(2):195-213. PMID: 19380060

Classics

  1. Hueston JT, Wilson WF, Soin K. Trigger thumb. Med J Aust 1973;2(23):1044-5. PMID: 4544198
  2. Sprecher EE. Trigger thumb in infants. J Bone Joint Surg Am 1949;31A(3):672-4. PMID: 18153912