Orthopaedic Surgery - Trigger Finger

Basics

Trigger finger is a form of:

Stenosing flexor tenosynovitis

that causes painful:

Catching

Clicking

or

Locking

of a digit during flexion and extension.

The condition develops when normal gliding between the:

Flexor tendon

and its surrounding:

Tendon sheath

becomes impaired.

Pathophysiology

The most common site of mechanical obstruction is the:

A1 pulley.

A thickened flexor tendon or tendon nodule passes with difficulty through this relatively narrowed pulley, producing:

Triggering.

Self-Perpetuating Mechanism

Repeated catching produces additional:

Mechanical irritation

and

Tendon swelling.

This may further worsen the mismatch between the tendon and:

A1 pulley.

Tendinopathy Rather Than Tendinitis

Histologic studies generally demonstrate:

Degenerative tendon and pulley changes

rather than prominent inflammatory-cell infiltration.

Therefore, adult trigger finger is more accurately considered a:

Stenosing tendinopathy

than a true inflammatory:

Tendinitis.

Quinnell Classification

Trigger finger severity may be graded using the:

Quinnell classification.

Grade 0

Pain with movement

without mechanical:

Catching or triggering.

Grade 1

There is:

Uneven movement

or

Clicking during flexion

but no true locking.

Grade 2

The digit:

Triggers

but the patient can actively:

Correct or extend it.

Grade 3

The digit triggers or locks and requires:

Passive correction

using the opposite hand.

Grade 4

The digit is:

Locked

or has developed a fixed:

Flexion contracture.

Pediatric Triggering

Pediatric trigger thumb and trigger fingers are now regarded as predominantly:

Acquired

rather than truly:

Congenital.

Their underlying mechanism differs from typical adult trigger finger.

Epidemiology

Triggering can involve:

Any digit.

Adults

In adults, the most commonly affected digits are:

Thumb

Ring finger

and

Middle finger.

Children

In children, the:

Thumb

is affected most frequently.

The:

Middle finger

is among the more frequently involved non-thumb digits.

Age

Trigger finger is particularly common in:

Middle-aged adults.

Pediatric cases usually present during:

Early childhood.

Sex

Adult trigger finger is more common in:

Women

than in men.

Incidence

The lifetime incidence in adults is approximately:

2.6%.

Diabetes

Among patients with diabetes, the incidence is substantially higher, historically reported around:

4–10%.

Multiple-digit involvement is also more common in:

Diabetes.

Pediatric Incidence

Pediatric trigger thumb occurs in approximately:

1–3 per 1,000 children.

Pediatric trigger fingers are much less common and have been reported to occur roughly:

10 times less frequently

than pediatric trigger thumb.

Pregnancy

Triggering may occur more frequently during:

Pregnancy

because of soft-tissue and fluid-related changes.

Symptoms may improve after:

Pregnancy.

Risk Factors

Important risk factors include:

Increasing age

Diabetes mellitus

and

Rheumatoid arthritis.

Other Associated Disorders

Trigger finger may also be associated with:

Gout

and other systemic conditions affecting:

Connective tissue or tendon sheaths.

Etiology

In adults, a thickened area or nodule may develop in the:

Flexor tendon.

Mechanical Impingement

The thickened tendon catches as it passes beneath the:

A1 pulley

at the level of the:

MCP joint.

Triggering

As the patient flexes and extends the digit, the tendon may suddenly pass through the narrowed pulley, producing:

Snapping

or

Locking.

Pediatric Trigger Thumb

In children approximately:

1–4 years of age

a nodular thickening of the flexor pollicis longus may be present.

This is commonly called a:

Notta node.

Notta Node

A Notta node may be palpable near the:

MCP flexion crease

and can prevent smooth passage of the tendon through the:

A1 pulley.

Pediatric Trigger Finger

Non-thumb trigger digits in children have a more complex and less well-understood:

Etiology.

Possible abnormalities include:

Anomalous lumbrical insertion into the flexor digitorum superficialis

or an abnormal relationship between the:

FDS

and

FDP tendons.

Associated Conditions in Children

Pediatric trigger fingers may be associated with:

Mucopolysaccharidoses

Juvenile idiopathic arthritis

Ehlers-Danlos syndrome

and

Down syndrome.

Associated Conditions in Adults

Adults may have associated conditions such as:

Carpal tunnel syndrome

or

de Quervain tenosynovitis.

Diagnosis

Trigger finger is primarily a:

Clinical diagnosis.

Signs and Symptoms

Typical findings include:

Pain

Tenderness

Clicking

and

Locking.

Palmar Nodule

A palpable nodule may be present along the:

Flexor tendon

near the:

Distal palmar crease.

A1 Pulley Tenderness

Tenderness is usually maximal over the:

A1 pulley.

Painful Locking

The digit may become locked in:

Flexion

and then release suddenly during:

Extension.

Snapping

Patients may describe a painful:

Snap

or

Pop

during movement.

Radiation of Pain

Pain may occasionally radiate proximally into the:

Palm

or

Forearm.

Physical Examination

Palpate the flexor tendon sheath at the level of the:

A1 pulley

while asking the patient to repeatedly:

Flex and extend the digit.

Palpable Triggering

The examiner may feel:

Tendon thickening

A nodule

or the actual:

Triggering event.

Examine All Digits

All digits should be examined because:

Multiple trigger digits

may occur, particularly in patients with systemic:

Disease.

Bilateral Pediatric Disease

Approximately:

25% of pediatric trigger-thumb cases

may have bilateral involvement.

Fixed Contracture

Chronic disease may produce a fixed:

PIP or IP flexion contracture.

Laboratory Tests

No serum laboratory study is specific for:

Trigger finger.

Systemic Disease Evaluation

Laboratory investigation is not routinely required but may be appropriate when an underlying systemic disorder such as:

Rheumatoid arthritis

Gout

or another metabolic disease is suspected.

Imaging

Imaging is usually:

Unnecessary.

Radiographs

Plain radiographs may be helpful when a fixed deformity raises concern for:

Arthritis

Joint contracture

Loose body

or other:

Bony pathology.

Ultrasound

Ultrasound can demonstrate thickening of the:

Flexor tendon

or

A1 pulley

but is not routinely required for diagnosis.

Differential Diagnosis

Important alternatives include:

Flexor tendon rupture

Joint contracture or ankylosis

Congenital clasped thumb

Extensor tendon deficiency

Tumor of the tendon sheath

and

Loose body within the MCP joint.

Treatment

Management depends on:

Age

Severity

Number of involved digits

and whether symptoms are:

Adult or pediatric in origin.

General Measures

Mild symptoms may temporarily improve with:

Rest

and

Activity modification.

Multiple Trigger Digits

Multiple symptomatic trigger digits may suggest:

Systemic disease

and may increase the likelihood that:

Surgical treatment

will eventually be required.

Pediatric Trigger Thumb

Many pediatric trigger thumbs may resolve:

Spontaneously.

Resolution may take as long as:

Several years.

Observation in Children

Observation is appropriate in selected young children without:

Fixed deformity

or progressive:

Contracture.

Timing of Pediatric Surgery

Persistent pediatric trigger thumb may require surgery, particularly when there is:

Fixed IP flexion contracture

or failure to improve with:

Growth.

Historically, release has often been considered before approximately:

4 years of age

when contracture is persistent.

Pediatric Trigger Finger

Non-thumb pediatric trigger fingers may be treated initially with:

Observation

or

Splinting

but are more likely than trigger thumb to involve:

Complex tendon abnormalities.

Adult Trigger Finger

In adults, first-line treatment commonly includes:

Corticosteroid injection.

Splinting

Splinting may be useful for:

Mild cases

particularly when the patient can comply consistently with:

Orthotic use.

Activity After Injection

Routine activity restrictions are usually unnecessary after:

Corticosteroid injection

although temporary avoidance of painful repetitive use may improve:

Comfort.

Physical Therapy

Formal physical therapy is generally:

Not required.

Hand Therapy

Selected patients may benefit from instruction regarding:

Splinting

Tendon gliding

and

Activity modification.

Medication

The principal medication treatment in adults is:

Corticosteroid injection.

Injection Technique

Corticosteroid, often combined with:

Local anesthetic

is injected into or adjacent to the:

Flexor tendon sheath

at the level of the:

A1 pulley.

Avoid Intratendinous Injection

Medication should not be injected directly into the:

Flexor tendon

because this may increase the risk of:

Tendon injury or rupture.

Injection Success

A single corticosteroid injection has historically produced improvement in approximately:

45–92% of patients.

Factors Associated With Injection Failure

Injection is less likely to succeed in patients with:

Diabetes

Multiple trigger digits

and sometimes younger patients with:

Long-standing symptoms.

Injection Complications

Potential complications include:

Skin depigmentation

Subcutaneous fat atrophy

Transient hyperglycemia

and, rarely,

Tendon attrition or rupture.

Surgery

Surgical release is indicated when symptoms persist despite appropriate:

Nonoperative treatment

or when the digit is:

Fixed or severely locked.

A1 Pulley Release

The standard procedure is:

Release of the A1 pulley.

Open Release

Open surgical release remains the most established and reliable:

Procedure.

Surgical Incision

A small:

Longitudinal

Transverse

or

Oblique incision

is made over the affected:

A1 pulley.

Pulley Division

The A1 pulley is carefully divided while protecting the adjacent:

Digital nerves

and

Digital vessels.

Persistent Triggering

If triggering persists after complete A1 pulley release, selected patients may require excision of the:

Ulnar slip of the FDS tendon.

Percutaneous Release

Some surgeons use:

Percutaneous A1 pulley release

in appropriately selected:

Adult patients.

Pediatric Trigger Finger Surgery

Pediatric non-thumb trigger fingers may require more extensive procedures, including:

Partial A2 pulley release

A3 pulley release

or

FDS slip excision.

Pediatric Trigger Thumb Surgery

Trigger-thumb release requires particular care because the:

Radial digital nerve

crosses near the operative:

Field.

Postoperative Care

The hand is usually covered with a:

Light dressing

for several days.

Motion

Early:

Finger motion

is generally encouraged after surgery to prevent:

Stiffness.

Activity

Normal activity is resumed:

Gradually

as wound healing and comfort permit.

Follow-Up

Follow-up after injection is based on:

Persistence or recurrence of symptoms.

After Surgery

After uncomplicated release, prolonged monitoring is usually:

Not necessary.

Prognosis

Overall prognosis is:

Good to excellent.

Corticosteroid Injection

Injection is less successful in patients with:

Diabetes mellitus

and may also be less effective when several digits are involved.

Surgical Success

Open A1 pulley release has a reported success rate exceeding:

97%.

Pediatric Prognosis

Open release provides highly reliable outcomes in:

Pediatric trigger thumb

and

Pediatric trigger finger.

Pediatric Recurrence

Recurrence after surgery is more common in pediatric:

Trigger fingers

than in pediatric:

Trigger thumbs.

Complications

Potential injection complications include:

Digital nerve injury

Vascular injury

Tendon injury

and

Skin changes.

These are generally:

Uncommon.

Surgical Complications

Potential surgical complications include:

Digital nerve laceration

Flexor tendon injury

Infection

Stiffness

Persistent triggering

and

Complex regional pain syndrome.

Recurrence

Incomplete release of the:

A1 pulley

or unrecognized additional pathology may lead to:

Persistent or recurrent triggering.

Patient Monitoring

Following successful surgical release, extensive long-term monitoring is usually:

Unnecessary.

Patients should return if they develop:

Recurrent triggering

Wound problems

Neurologic symptoms

or persistent:

Stiffness.

Clinical Summary

Typical presentation: Painful clicking, catching, or locking of a finger during flexion and extension, with tenderness over the A1 pulley.

Key pathology: Thickening of the flexor tendon and/or A1 pulley causes impaired tendon gliding.

Most commonly affected adult digits: Thumb, ring finger, and middle finger.

Diagnosis: Primarily clinical; imaging and laboratory tests are usually unnecessary.

First-line adult treatment: Corticosteroid injection into or around the flexor tendon sheath, with splinting as an option in mild cases.

Surgery: A1 pulley release is indicated for persistent, recurrent, fixed, or severe triggering and has a very high success rate.

Pediatric trigger thumb: Often observed initially because spontaneous resolution can occur, but persistent fixed contracture may require surgical release.

Important association: Trigger finger is more common and often more resistant to injection in patients with diabetes mellitus.

Key Principle

Trigger finger is a stenosing flexor tenosynovial disorder caused by impaired passage of the flexor tendon through the A1 pulley.

The characteristic findings are:

Tenderness over the A1 pulley, a palpable tendon nodule, and painful clicking, catching, or locking.

Diagnosis is almost always:

Clinical.

In adults, treatment usually begins with:

Corticosteroid injection, while persistent or severe disease is treated with:

A1 pulley release.

Children, particularly those with:

Trigger thumb, have a different natural history and may initially be observed, but persistent fixed contracture warrants:

Surgical evaluation.