Pediatric Trigger Thumb

Kids get their hands and fingers into a lot of trouble sometimes!  We’ve talked about some pediatric hand injury patterns such as scaphoid fractures, finger fractures, and metacarpal fractures.  There are other maladies that affect fingers such as hair tourniquets and nailbed lacerations.  I recently saw a toddler who had thumb pain and swelling with decreased range of motion after getting the thumb stuck in the crevices between a couch and console, but there was no fracture.  The tot turned out to have a trigger thumb, which prompted me to explore this topic more.  Let’s discuss pediatric trigger thumb, how and when it happens, and what you need to do about it!

Pediatric Trigger Thumb – Basics

  • Condition in young pediatric patients resulting in abnormal flexion of the interphalangeal joint of the thumb[Watts 2021, Baek 2011]
  • This is different than adult acquired trigger thumb
  • 3 per 1,000 children diagnosed within the first year of life [Watts 2021, Kikuchi 2006]
  • Equally affects males and females 
  • One quarter of diagnoses are bilateral 
  • Etiology is still unclear

Pediatric Trigger Thumb – Pathophysiology

  • The flexor pollicis longus (FPL) tendon becomes abnormally thickened [Watts 2021]
  • The tendon’s increased diameter impedes easy gliding through the A1 pulley sheath [Watts 2021]
  • Acquired condition usually. There is some suggestion of genetic autosomal dominant but variable penetration. [Watts 2021]
  • So, it’s not really a congenital condition [Watts 2021, Kikuchi 2006]

Pediatric Trigger Thumb – Presentation and Exam

  • Children… well, really their parents… complain of a fixed flexion deformity at the IP joint of the thumb [Watts 2021]
  • Trauma is not often associated with the condition
  • Family history of this is also rare
  • Symptoms [Watts 2021]
    • Usually painless, sometimes found bilaterally
    • Exam: flexion deformity at the IP joint
    • Flexor tendon nodule = “Notta’s Node” prevents sliding of tendon in sheath
    • Notta’s node can be visible and palpable on exam

Pediatric Trigger Thumb – Evaluation and Diagnosis 

  • Usually, the diagnosis is made clinically when exam shows a flexion deformity at the IP joint of the thumb [Watts 2021]
  • Radiology – AP and lateral views recommended if there is a history of trauma. (Maybe dedicated thumb views.) [Watts 2021]
    • Look for alternatives to trigger thumb
    • If no trauma, the Xrays will likely be normal.
  • Grading [Jung 2012]
    • 0A – extension beyond 0°
    • 0B – extension to 0°
    • 1 – active extension with triggering
    • 2 – passive extension with triggering
    • 3 – cannot extend either actively or passively/locked

Pediatric Trigger Thumb – Treatment 

  • Most often this is treated non-operatively with splinting [Watts 2021, Baek 2011]
    • Intermittent extension splinting – first line treatment.
      • More successful than observation only [Watts 2021, Sirithiantong 2021]
      • Works better with concurrent stretching plan
      • Best for flexible deformity. Not beneficial for fixed deformities
      • Keeps IP joint in hyperextension for 6-12 weeks
      • 50-67% resolution for all ages [Watts 2021, Nemoto 1996, Farr 2014]
      • Chalise et al reported 72% success rate with splinting [Chalise 2013]
      • Koh reported 92% success with splinting vs 60% with observation [Koh 2012]
    • Passive extension exercises for thumb and observation will work 30-60% of the time before 2 years of age. [Watts 2021, Dunsmuir 2000, Farr 2014]
      • <10% spontaneously resolve after 2 yrs old.
      • Not beneficial for older children with fixed deformities
      • Cases with bilateral involvement or locking have less success with stretching alone- should consider early surgery [Jung 2012]
  • Persistent and fixed deformities may be treated surgically with an open A1 pulley release after their first birthday. [Watts 2021]
    • Also beneficial if conservative management has failed.
    • 65-95% success rate [Watts 2021, Chalise 2013, Farr 2014]
    • Open surgery includes an incision over the thumb MCP flexion crease, release of the A1 pully, finding the Notta node, and observing FPL gliding smoothly through released A1.
    • Successful even in older children or delayed diagnosis [Han 2010, Baek 2011]
  • Amrani et al describe 48 percutaneous trigger thumb releases that were successful out of 50
    • Wang et al reported 90% percutaneous success [Wang 2005]
  • A systematic review found that open surgery, percutaneous surgery, and splinting were all better than observation and stretching alone. [Sirithiantong 2021]
    • Percutaneous surgical release had higher recurrence compared to open surgical release
    • Open surgical release had the best cure rate followed by splinting
    • But open release had higher recurrence rate than splinting
    • Recommended splinting as appropriate first line therapy with open release if splinting fails.

Pediatric Trigger Thumb- Complications

  • Complications of operative A1 pulley release [Watts 2021, Ryzewicz 2006]
    • Radial digital nerve injury
    • Scar contracture
    • Infections 
    • IP flexion deficit
    • Bow-stringing of flexor tendon
  • Complications of untreated trigger thumb
    • Decreased grasping ability of hand
    • Visual annoyance

Moral of the Morsel

  • You may encounter pediatric trigger thumb in an older infant or toddler
    • You can get Xrays to evaluate for fracture if there was trauma, otherwise, this is a clinical diagnosis
  • Conservative management with splinting is an excellent and successful first line therapy
    • Open surgical release of the A1 trigger pulley sheath works for those who fail conservative management
    • There is no rush for surgery, as successful splinting may take many months
  • While you shouldn’t offer a ride to a stranger thumbing it on the highway, you can certainly now offer treatment advice for their trigger thumb!

References:

  1. Watts, MD, E., 2021. Congenital Trigger Thumb. [online] Orthobullets.com. Available at: <https://www.orthobullets.com/hand/6084/congenital-trigger-thumb> [Accessed 2 July 2022].
  2. 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 Jun;3(2):157-9. doi: 10.4055/cios.2011.3.2.157. Epub 2011 May 12. PMID: 21629478; PMCID: PMC3095788.
  3. Kikuchi N, Ogino T. Incidence and development of trigger thumb in children. J Hand Surg Am. 2006;31(4):541-543. doi:10.1016/j.jhsa.2005.12.024
  4. Jung HJ, Lee JS, Song KS, Yang JJ. Conservative treatment of pediatric trigger thumb: follow-up for over 4 years. J Hand Surg Eur Vol. 2012;37(3):220-224. doi:10.1177/1753193411422333
  5. Sirithiantong T, Woratanarat P, Woratanarat T, et al. Network meta-analysis of management of trigger thumb in children. J Pediatr Orthop B. 2021;30(4):351-357. doi:10.1097/BPB.0000000000000809
  6. Nemoto K, Nemoto T, Terada N, Amako M, Kawaguchi M. Splint therapy for trigger thumb and finger in children. J Hand Surg Br. 1996;21(3):416-418. doi:10.1016/s0266-7681(05)80221-9
  7. Farr S, Grill F, Ganger R, Girsch W. Open surgery versus nonoperative treatments for paediatric trigger thumb: a systematic review. J Hand Surg Eur Vol. 2014;39(7):719-726. doi:10.1177/1753193414523245
  8. Chalise PK, Mishra AK, Shah SB, Adhikari V, Singh RP. The treatment of trigger thumb in children: conservative or surgical?. Nepal Med Coll J. 2013;15(2):122-124.
  9. Koh S, Horii E, Hattori T, Hiroishi M, Otsuka J. Pediatric trigger thumb with locked interphalangeal joint: can observation or splinting be a treatment option?. J Pediatr Orthop. 2012;32(7):724-726. doi:10.1097/BPO.0b013e318264484c
  10. Dunsmuir RA, Sherlock DA. The outcome of treatment of trigger thumb in children. J Bone Joint Surg Br. 2000;82(5):736-738. doi:10.1302/0301-620x.82b5.10250
  11. Han SH, Yoon HK, Shin DE, Song DG. Trigger thumb in children: results of surgical treatment in children above 5 years of age. J Pediatr Orthop. 2010;30(7):710-714. doi:10.1097/BPO.0b013e3181edef8d
  12. Amrani A, Dandane MA, Alami ZF. Le traitement percutané du pouce à ressaut chez l’enfant : à propos de 63 cas [Percutaneous release of trigger thumb in children: 63 cases]. Chir Main. 2011;30(2):102-104. doi:10.1016/j.main.2011.01.012
  13. Wang HC, Lin GT. Retrospective study of open versus percutaneous surgery for trigger thumb in children. Plast Reconstr Surg. 2005;115(7):1963-1972. doi:10.1097/01.prs.0000165068.57709.4a
  14. Ryzewicz M, Wolf JM. Trigger digits: principles, management, and complications. J Hand Surg Am. 2006;31(1):135-146. doi:10.1016/j.jhsa.2005.10.013
Christyn Magill
Christyn Magill
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