Trigger Finger

By admin On Mar 16, 2024

Ovid: 5-Minute Orthopaedic Consult

Editors: Frassica, Frank J.; Sponseller, Paul D.; Wilckens, John H.

Title: 5-Minute Orthopaedic Consult, 2nd Edition

> Table of Contents > Trigger Finger

Trigger Finger

Dawn M. LaPorte MD

Chris Hutchins MD

Basics

Description

A “trigger finger” is a manifestation of
stenosing tenosynovitis that results in painful catching of the
involved flexor tendon as the patient flexes and extends the digit.
As the affected digit is slowly flexed, it snaps or triggers into a flexed position.
Once the digit triggers, extension is difficult and, occasionally, must be obtained manually.

Pregnancy Considerations

Incidence in pregnant females may be higher than that in the general population.
Treat with corticosteroid injection for temporary triggering relief because it likely will resolve or not recur.

Epidemiology

Affected digits:
- In the adult, all digits, but most commonly, the thumb, ring, and middle fingers
- In the child, primarily the thumb
Children (congenital type) and middle-aged patients predominate.
The adult variety of trigger finger is more common in females than in males.

Incidence

The lifetime incidence in nondiabetic adults >30
years old is reported to be 2.2% and that in adults with
insulin-dependent diabetes mellitus is up to 10% (1).

Risk Factors

Rheumatoid arthritis
Increased age
Diabetes mellitus

Etiology

A nodule usually develops on the flexor tendon, most likely in response to abrasion of the tendon in the tendon sheath.
The nodule then impinges on one of the
rings of fibrous tissue encircling the flexor tendon sheath known as
the A1 pulley; the result is “triggering” when the digit is extended (Fig. 1).
This problem is self-perpetuating because the irritation from triggering prevents a decrease in the swelling.
In the pediatric population (<2 years
old), a congenital narrowing of the tendon sheath or a nodular
thickening in the tendon (Notta node) may be present, resulting in
congenital trigger digit, most commonly the thumb.

Associated Conditions

In congenital trigger digit, an association with trisomy 13 exists.
In the adult patient, other disorders related to tenosynovitis, such as de Quervain tenosynovitis and CTS, may be present.
Systemic disorders that cause connective
tissue abnormalities, such as diabetes, gout, and rheumatoid arthritis,
also may be present.

Diagnosis

Signs and Symptoms

Sign: A nodule in the palm of the hand, just distal to the distal palmar crease
Symptom: Painful locking or snapping of the digit into a flexed position with flexion

Physical Exam

By gently palpating the flexor tendon
sheath of the affected digit in the region of the distal palmar crease
and then having the patient flex the digit, the offending nodule and/or
triggering sometimes may be palpated.
In children <2 years old, 30% have bilateral involvement (2–4).

Tests

Lab

No serum laboratory tests aid in this diagnosis.

Imaging

Imaging studies usually are not necessary because trigger finger is a clinical diagnosis.

Fig. 1. In trigger finger, a nodule in the tendon sheath prevents it from sliding under the pulley. The finger does not extend.

Differential Diagnosis

Tendon rupture
Contracted (ankylosed) joints
Congenital clasped thumb
Absent extensor
Tumor of tendon sheath
Loose body in the MCP joint

Treatment

General Measures

Triggering may unlock with rest.
In children:
- <6 months old: 30% resolve spontaneously (2).
- 6–30 months old: Only 12% resolve spontaneously (2).
- Many require surgical intervention, which
  is recommended before 4 years of age to prevent permanent contracture
  of the IP joint (5)
In adults: Corticosteroid injection is 1st line of treatment.
When nonoperative therapy fails, surgical incision of the A1 pulley has a 98% cure rate.
No restrictions are placed on activity after injection.

Special Therapy

Physical Therapy

None is needed.

Medication

First Line

In adults, treatment commences with
injection of the tendon sheath (but not the tendon) with lidocaine and
cortisone in the region of the A1 pulley.
- A single injection results in a 44–93% success rate (6–8).
- The use of >3 injections has a 77–88% success rate (6–8).

Surgery

A small transverse or oblique incision is
made in the region of the A1 pulley (just distal to the distal
transverse palmar crease) and overlying the affected flexor tendon.
The A1 pulley is incised.
After surgical release, the hand is bandaged for several days.
Activity is resumed gradually.

P.473

Follow-up

Prognosis

The prognosis is good.

Complications

Errant injections may result in damage to the tendon or digital nerves and vasculature, but these complications are rare.
Surgical risks include digital nerve laceration, tendon rupture, infection, and reflex sympathetic dystrophy.

Patient Monitoring

None is necessary after surgical release.

References

1. Stahl S, Kanter Y, Karnielli E. Outcome of trigger finger treatment in diabetes. J Diabet Complications 1997;11:287–290.

2. Dinham
JM, Meggitt BF. Trigger thumbs in children. A review of the natural
history and indications for treatment in 105 patients. J Bone Joint Surg 1974;56B:153–155.

3. Ger E, Kupcha P, Ger D. The management of trigger thumb in children. J Hand Surg 1991;16A:944–947.

4. Wood VE, Sicilia M. Congenital trigger digit. Clin Orthop Relat Res 1992;285:205–209.

5. Wolfe
SW. Tenosynovitis. In: Green DP, Hotchkiss RN, Pederson WC, et al, eds.
Green’s Operative Hand Surgery, 5th ed. Philadelphia: Elsevier
Churchill Livingstone, 2005:2137–2159.

6. Freiberg A, Mulholland RS, Levine R. Nonoperative treatment of trigger fingers and thumbs. J Hand Surg 1989;14A:553–558.

7. Griggs SM, Weiss APC, Lane LB, et al. Treatment of trigger finger in patients with diabetes mellitus. J Hand Surg 1995;20A:787–789.

8. Rhoades
CE, Gelberman RH, Manjarris JF. Stenosing tenosynovitis of the fingers
and thumb. Results of a prospective trial of steroid injection and
splinting. Clin Orthop Relat Res 1984;190: 236–238.

Additional Reading

Lister G. Inflammation. In: The Hand: Diagnosis and Treatment,3rd ed. New York: Churchill Livingstone; 1993:323–353.

Miscellaneous

Codes

ICD9-CM

727.03 Trigger finger, acquired
756.89 Congenital

Patient Teaching

Patients are advised to have surgical release for recurrent symptoms.

FAQ

Q: What is the initial treatment for a trigger digit?

A: Most trigger digits in adults can be treated successfully with corticosteroid injection.

Q: Is trigger digit associated with any medical comorbidities, and does this affect prognosis?

A:
“Secondary” trigger digit can be associated with diabetes mellitus,
gout, renal disease, rheumatoid arthritis, and other rheumatic
diseases. It is associated with a worse prognosis after nonoperative or
operative management.