High Yield Topics

Trigger Finger

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Ovid: 5-Minute Sports Medicine Consult, The


Trigger Finger
Yvonne Chow
Rahul Kapur
Basics
Description
  • Also called flexor tenosynovitis
  • Type of stenosing tenosynovitis
  • Nodule on flexor tendon catching on A1 pulley
  • Can affect any digit; occasionally, multiple digits
  • Ring and middle digit involvement most common in adults
  • Almost exclusively thumb in children
  • Diffuse versus nodular versus “congenital” (pediatric trigger thumb)
Epidemiology
  • Predominant gender: Female > Male (3–6× more common in females).
  • Predominant age: Bimodal: Age <8 yrs and 55–60 yrs
  • Seen more commonly in dominant hand
  • Lifetime risk 2.6% in general population but 10% in diabetics
Incidence
28 cases/100,000 population
Risk Factors
  • Diabetes, rheumatoid arthritis (RA), connective tissue disorders
  • Repetitive trauma with compressive force against metacarpophalangeal (MCP) area (eg, arc welding)
General Prevention
Activity modification
Etiology
  • Inflammation of flexor digitorum superficialis (FDS) tendon leading to nodule formation
  • 1st annular (A1) pulley spans from volar plate of distal metacarpal to base of proximal phalanx.
  • Nodule catches on A1 pulley during finger flexion, leading to pain.
  • Pain often greatest at MCP joint
  • Generally idiopathic
  • Can result from repetitive trauma or sepsis from secondary infection (eg, tuberculosis)
Commonly Associated Conditions
  • Diabetes
  • RA
  • Hypothyroidism
  • Amyloidosis
  • Mucopolysaccharidosis
  • Connective tissue disorders
Diagnosis
History
  • Painful catching/clicking with finger flexion or extension
  • Pain over MCP; may refer to palm or proximal interphalangeal (PIP) joint
  • Digit may be locked, usually in flexion.
  • Stiffness develops with prolonged symptoms.
Physical Exam
  • Tender, palpable nodule on flexor tendon
  • Active fist closing reproduces lock/snap.
Diagnostic Tests & Interpretation
Lab
None indicated, except to evaluate associated systemic disease.
Imaging
None indicated; x-rays may be considered to rule out differentials.
Diagnostic Procedures/Surgery
None; steroid injection is both therapeutic and diagnostic.
Differential Diagnosis
  • Dupuytren contracture
  • Carpal tunnel syndrome
  • Gamekeeper's thumb
  • RA
  • Tendon sheath ganglion
  • Suppurative tenosynovitis
Treatment
  • Activity modification
  • Splinting of MCP joint at 10–15 degrees of flexion ×6–10 wks:
    • Reduces tendon motion in sheath
    • Allows resolution of surrounding synovitis
    • 93% with partial or full symptom resolution after 10 wks (1)[B]

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Medication
First Line
Injected corticosteroids (see “Surgery/Other Procedures” below)
Second Line
NSAIDs may help with pain relief; no specific evidence but commonly recommended.
Surgery/Other Procedures
  • Corticosteroid injection into tendon sheath:
    • Palmar or dorsolateral approach to avoid neurovascular bundle
    • US guidance may maximize accuracy (2)[B].
    • SC infiltration equal or superior to intrasheath injection (3)[B].
    • May require repeat injection in 1 mo
    • Up to 93% complete or partial reduction of symptoms in nodular type (4)[A]
    • Only 50% response in diffuse type or diabetes
  • Surgical release of A1 pulley:
    • Open or percutaneous procedure
    • 1st-line treatment for locked digit or pediatric trigger thumb, although there is increasing argument toward conservative management for the latter
    • Indicated if repeat injections ineffective
    • 97% complete resolution of symptoms (4)[A]
Ongoing Care
Follow-Up Recommendations
Patient Monitoring
May see increased glucose level following steroid injection in diabetes
Prognosis
  • Excellent; over 90% symptom resolution with steroid or surgical therapy
  • 23–63% of pediatric trigger digits may resolve spontaneously.
Complications
  • If untreated:
    • PIP joint flexion contracture
    • Distal triggering from FDS tendon degeneration
  • Of injection:
    • Fat atrophy and necrosis
    • Local skin depigmentation
    • Theoretical risk of tendon rupture
  • Of surgical release:
    • Bowstringing of flexor tendon
    • A2 pulley injury
    • Digital nerve injury
    • Infection
    • Long-term scar tenderness
References
1. Colbourn J, Heath N, Manary S, et al. Effectiveness of splinting for the treatment of trigger finger. J Hand Ther. 2008;21:336–343.
2. Bodor M, Flossman T. Ultrasound-guided first annular pulley injection for trigger finger. J Ultrasound Med. 2009;28:737–743.
3. Kazuki K, Egi T, Okada M, et al. Clinical outcome of extrasynovial steroid injection for trigger finger. Hand Surg. 2006;11:1–4.
4. Nimigan AS, Ross DC, Gan BS. Steroid injections in the management of trigger fingers. Am J Phys Med Rehabil. 2006;85:36–43.
Additional Reading
Akhtar S, Bradley MJ, Quinton DN, et al. Management and referral for trigger finger/thumb. BMJ. 2005;331:30–33.
Ryzewicz M, Wolf JM. Trigger digits: principles, management, and complications. J Hand Surg [Am]. 2006;31:135–146.
Codes
ICD9
727.03 Trigger finger (acquired)
Clinical Pearls
  • Clinical diagnosis by painful catching at MCP joint
  • Corticosteroid injection is safe and highly effective 1st-line treatment.
  • Surgical release provides excellent results when conservative measures fail.
  • Trigger finger in diabetics is less likely to respond to steroid therapy.


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