What is congenital trigger Thumb/Finger?
Trigger thumb represents an abnormality of the flexor pollicis longus and its tendon sheath at the Al pulley. There is a palpable mass (Notta nodule), representing the flexor pollicis longus constriction at the Al pulley.
Is it always congenital?
In the past,trigger thumbs were defined as congenital. However, this
condition is acquired in the first
2 years of life, as indicated
by prospective screening of neonates who failed to yield any
What causes CTT/CTF?
The cause appears to be a size mismatch between the flexor pollicis longus and the Al pulley that leads to progressive constriction. Unlike adult trigger digits, there does not appear to be an inflammatory component.
Can it be hereditary or associated with syndromes?
There is no familialinheritance pattern.30% of the cases are bilateral. Isolated trigger thumbs have no associated syndromes. However,trigger digits are seen with neurologic syndromes (trisomy18) and mucopol
When and how does a child with TT/TF present?
Trigger thumb patients present at ages ranging from infancy to school age. Often, the diagnosis is missed until local trauma brings attention to the thumb. In the emergency setting the flexed interphalangeal joint can be mistaken for an interphalangeal joint dislocation.Radiographs are misleading because of limited phalangeal ossification. A palpable nodule at the Al pulley is diagnostic.If the trigger is long-standing, compensatory hyperextension
of the MCP joint develops to effectively bring the thumb out of the palm. In addition, there may develop mild radial deviation of the interphalangeal joint secondary to eccentric flexor pull.
How is CTT/CTF treated?
In infants younger than 9 months of age, Dinham and Meggit found that 30% of trigger thumbs may resolve spontaneously. In infants older than 1 year of age, less than 10% of trigger thumbs resolved spontaneously. Ger et al.found lack of resolution with observation for 3 years in their patients. There is limited evidence that splinting will be of benefit, and often it is not well tolerated. Surgical release of the constricting Al pulley and flexor tendon sheath is the treatment of choice.
What are the indications for surgery
This is indicated in infants without spontaneous resolution by 1 year of age, and in any toddler or older child presenting with a locked trigger thumb.
What are the steps of the surgery?
- Anaesthesia general with local block
- Incision: Transversely in the digital crease to lessen scarring.
- Deeper dissection: Perpendicular to incision. Care must be taken to avoid iatrogenic injury to the superficial digital neurovascular bundles. A1 pulley is releasd.
- It is usually not necessary to excise a portion of this pulley nor to shave the nodule, which will disappear after the release.The oblique pulley needs to be preserved to prevent
flexor tendon bowstringing.
- The thumb is extended fully to be certain that the release is complete.
- On ly the skin is closed
- The thumb is placed in a light (child-proof) dressing for 1 week and then removed to allow return to the usual activities. No further treatment is required. The chance of recurrance are very few
How is trigger finger different from rigger thumb?
- Trigger digits are more often multiple, and can be associated with central nervous system disorders and syndromes (trisomy 18, mucopolysaccharidoses).
- The pathology appears to predominate at the decussation of the flexor tendons under the A2 pulley, and not at the Al pulley alone.
- Th e tri ggering appears to occur as the flexor digitorum profundus passes through the chiasm of the flexor digitorum superficialis.
- Surgic al recurrence is high in pediatric trigger digits. This may be because Al pulley release alone is not sufficient to solve the problem. Further opening of the chiasm or resection of a slip of the flexor digitorum superficialis is often necessary to prevent recurrence
The Natural History of Pediatric Trigger Thumb
Goo Hyun Baek, MD, Ji Hyeung Kim, MD, Moon Sang Chung, MD, Seung Baik Kang, MD, Young Ho Lee, MD and Hyun Sik Gong, MD
Department of Orthopedic Surgery, Seoul National University College of Medicine, 28 Yongon-dong, Chongno-gu, Seoul 110-744, South Korea. E-mail address for G.H. Baek: firstname.lastname@example.org
Investigation performed at the Department of Orthopedic Surgery, Seoul National University College of Medicine, Seoul, South Korea
Background: Pediatric trigger thumb is a condition of flexion deformity of the interphalangeal joint in children. Although the surgical outcome is satisfactory, the indications for nonoperative treatment for this condition are not clear. The aim of the present study was to determine the rate of resolution of untreated pediatric trigger thumb.
Methods: Data on seventy-one thumbs in fifty-three children were collected prospectively. The dates of the first visits ranged from April 1994 to March 2004. Patients were diagnosed with pediatric trigger thumb during initial outpatient department visits. During the present study, no treatment such as passive stretching or splinting was applied. The amount of flexion deformity at the thumb interphalangeal joint was measured at every six-month follow-up visit, and the duration of follow-up was at least two years after diagnosis. The end point of follow-up was when the deformity caused pain or secondary deformity or prevented normal use of the hand. The median duration of follow-up was forty-eight months.
Results: Of the seventy-one trigger thumbs, forty-five (63%) resolved spontaneously. The median time from the initial visit to resolution was forty-eight months. There was no significant difference in the pattern of resolution between patients with unilateral and bilateral trigger thumb. Although resolution was not observed in the remaining twenty-six thumbs, flexion deformities improved in twenty-two thumbs. For the first two years after the initial visit, the mean flexion deformity significantly decreased over the one-year intervals (p < 0.05).
Conclusions: Pediatric trigger thumb can be expected to resolve without treatment in >60% of patients. Moreover, the flexion deformity can be expected to show an improving pattern in patients who do not have resolution. This information may help both parents and surgeons to make decisions regarding the treatment of pediatric trigger thumb.