Trigger Finger

By admin Last updated Nov 11, 2023

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]

P.611

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)