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Pediatric Trigger Thumb (Congenital)

Test, Exam and Sign Description

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.

Differential Diagnosis

  • Thumb fracture
  • Thumb dislocation
  • Congenital absence of extensor tendon
  • Arthrogryposis

 

SYMPTOMS

  • Fixed-flexion deformity of the thumb IP joint
  • Flexor tendon nodule (Notta’s node)
  • Usually painless but may be tender on examination of the A-1 pulley area.
Presentation Photos and Related Diagrams
  • Left Pediatric Trigger Thumb
    Left Pediatric Trigger Thumb
Definition of Positive Result
  • A positive (abnormal) exam will demonstrate a thumb that clicks in and out of flexion with tenderness at the A-1 pulley area with or without swelling in the A-1 pulley area consistent with a Notta's node.
Definition of Negative Result
  • A negative (normal) esam will demonstrte a thumb with a normal smooth arc of active lexion and extension with no clicking, no tendenderness at the A-1 pulley and no Notta's node.
Comments and Pearls
  • 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.
Diagnoses Associated with Tests, Exams and Signs
TRIGGER THUMB PEDIATRIC
References

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