Orthopaedic Surgery - Thumb Ligament Injuries

Basics

Thumb ligament injuries most commonly involve the:

Ulnar collateral ligament of the metacarpophalangeal joint.

The injury may be:

Partial

or

Complete

and frequently occurs at the ligament’s distal attachment to the:

Base of the proximal phalanx.

Mechanism

The classic mechanism is forceful:

Radial deviation

or

Abduction of the thumb MCP joint.

This places excessive tension on the:

Ulnar collateral ligament.

Radial Collateral Ligament Injury

The:

Radial collateral ligament

of the thumb MCP joint may also be injured.

This usually occurs after excessive:

Adduction

of the thumb.

RCL injuries are less common than:

UCL injuries.

Ligament Tear Versus Avulsion Fracture

The injury may consist of:

Pure ligament rupture

or

Avulsion of a small fragment of bone

from the ligament’s attachment.

Classification

Thumb collateral ligament injuries are generally classified as:

Incomplete tears

or

Complete tears

according to the integrity of the:

Ligament and its bony attachment.

Synonyms

An acute thumb MCP UCL injury is commonly called:

Skier’s thumb.

A chronic UCL injury is historically termed:

Gamekeeper’s thumb.

Skier’s Thumb

Skier’s thumb usually results from an acute:

Hyperabduction injury

such as a fall while the thumb is caught against a:

Ski pole.

Gamekeeper’s Thumb

Gamekeeper’s thumb refers to chronic attenuation or insufficiency of the:

UCL

from repetitive:

Valgus stress.

Interphalangeal Joint Injuries

Collateral ligament injuries of the thumb:

Interphalangeal joint

are less common.

The IP joint is primarily a:

Hinge joint

and injuries may include:

Collateral ligament sprain

or

Dislocation.

Trapeziometacarpal Joint Injuries

Ligament injuries of the:

Trapeziometacarpal joint

are also less common.

They are often associated with:

CMC dislocation or subluxation.

Important TMC Ligaments

TMC dislocation may injure the:

Dorsoradial ligament

and

Anterior oblique ligament.

These structures contribute substantially to:

Thumb CMC stability.

Prevention

Prevention centers on avoiding mechanisms that force the thumb into excessive:

Abduction

or

Adduction.

Sports Prevention

Athletes should avoid situations where the thumb becomes caught during:

Falls

Ball handling

or contact with:

Equipment.

Epidemiology

Thumb ligament injuries occur in:

Men and women

and can affect:

All age groups.

Risk Factors

Common risk factors include:

Skiing accidents

and sports involving:

Ball handling

or sudden:

Thumb impact.

Associated Sports

Examples include:

Baseball

Football

and

Basketball.

Etiology

The classic UCL injury is caused by forceful:

Radial deviation of the thumb.

This produces excessive tension on the ligament and may result in:

Partial tearing

Complete rupture

or

Bony avulsion.

Associated Conditions

A UCL injury may be associated with:

Avulsion fracture

or a:

Stener lesion.

Stener Lesion

A Stener lesion occurs when a completely ruptured:

Ulnar collateral ligament

retracts proximally and becomes displaced superficial to the:

Adductor aponeurosis.

Importance of a Stener Lesion

The interposed adductor aponeurosis prevents the torn ligament from returning to its normal:

Anatomic insertion.

As a result, spontaneous healing is unlikely.

Clinical Clues to a Stener Lesion

Patients may demonstrate:

Marked swelling

Ecchymosis

and sometimes a palpable:

Ulnar-sided mass

at the MCP joint.

Diagnosis

Diagnosis is based on:

History

Physical examination

and

Imaging.

Signs and Symptoms

Typical symptoms include:

Pain

Swelling

and

Bruising

along the:

Ulnar side of the thumb MCP joint.

Deformity

Some patients have visible deformity near the:

Ulnar base of the thumb.

Functional Loss

Patients frequently report difficulty with:

Pinching

Gripping

and

Opening containers.

Loss of stable pinch is especially characteristic of significant:

UCL insufficiency.

Physical Examination

Examine the thumb for:

Swelling

Ecchymosis

Tenderness

and palpable:

Abnormality.

Palpable Mass

A local ulnar-sided mass may represent:

Retracted ligament

Stener lesion

or

Avulsed bone fragment.

Stability Testing

The MCP joint should be stressed in:

Extension

and at approximately:

30° of flexion.

Testing in Extension

Valgus stress in full or near-full extension assesses both:

Accessory collateral ligament structures

and overall:

MCP stability.

Testing in Flexion

Testing at approximately:

30° of MCP flexion

better isolates the:

Proper ulnar collateral ligament.

Comparison With the Opposite Thumb

Stability should be compared with the:

Contralateral uninjured thumb.

Complete Tear

Findings suggesting a complete tear include:

Absence of a firm endpoint

or approximately:

More than 15° greater laxity than the opposite side.

Absolute angular thresholds vary because normal ligament laxity differs between:

Individuals.

The quality of the endpoint is therefore especially important.

Radiographs Before Stress Examination

Plain radiographs should be reviewed before aggressive:

Stress testing.

This is important because an associated fracture may be displaced by:

Forceful examination.

Digital Block

In acute injuries, pain and swelling may prevent reliable examination.

A:

Digital nerve block

may allow more accurate assessment of:

Ligament stability.

TMC Joint Examination

The trapeziometacarpal joint should also be examined when clinically indicated.

The examiner translates the:

First metacarpal

relative to the:

Trapezium.

TMC Instability

Pain and excessive translation suggest:

CMC ligament injury.

Imaging

Plain Radiographs

Acute thumb injuries should undergo plain radiography to assess for:

Fracture

and

Joint alignment.

Avulsion Fracture

Radiographs may demonstrate a small bony fragment at the:

Base of the proximal phalanx

corresponding to:

UCL avulsion.

Chronic Injuries

In chronic ligament insufficiency, radiographs help assess for:

Joint subluxation

and

Degenerative arthritis.

Stress Radiographs

Stress radiographs may occasionally demonstrate:

Abnormal MCP opening

although they are less commonly required when examination and advanced imaging are:

Diagnostic.

MRI

MRI provides detailed information regarding:

Ligament continuity

Retraction

Stener lesion

and associated:

Cartilage or joint damage.

Ultrasound

Ultrasound may also assess:

Ligament integrity

and can identify displacement suggestive of a:

Stener lesion.

Its accuracy depends considerably on:

Operator experience.

Pathological Findings

Pathology may demonstrate:

Attenuation

or

Complete rupture

of the UCL.

Displaced Ligament

In a Stener lesion, the torn ligament lies superficial to the:

Adductor aponeurosis

rather than adjacent to its normal:

Distal insertion.

Differential Diagnosis

Important alternatives include:

First metacarpal fracture

Proximal phalanx fracture

First CMC arthritis

and

Volar plate injury.

Treatment

Treatment depends on:

Ligament involved

Completeness of rupture

Joint stability

Fracture displacement

and whether the injury is:

Acute or chronic.

Incomplete UCL Tear

Partial tears can generally be treated:

Nonoperatively.

Acute Partial Tear

Initial treatment includes:

Rest

Elevation

Ice

Analgesia

and

Thumb-spica immobilization.

Immobilization Duration

A partial ligament tear is commonly immobilized for approximately:

4 weeks.

If an associated stable avulsion fracture is present, immobilization may continue for up to:

6 weeks.

Chronic Partial Injury

Chronic but stable symptoms may be treated with:

Thumb-spica bracing

Activity modification

and rehabilitation.

Persistent instability may require:

Elective repair or reconstruction.

Complete UCL Tear

A complete acute rupture, particularly one associated with:

Instability

or

Stener lesion

generally requires:

Surgical repair.

Avulsion Fracture

Treatment of an avulsion fracture depends on:

Fragment size

Displacement

and

Joint stability.

Options include:

Ligament repair

Fracture fixation

or selected:

Fragment excision.

Stener Lesion

A confirmed Stener lesion requires:

Operative treatment

because the interposed:

Adductor aponeurosis

prevents normal ligament healing.

Chronic Complete Tear

Delayed or chronic complete tears frequently require:

Ligament reconstruction

rather than simple:

Primary repair.

Radial Collateral Ligament Injuries

RCL injuries are managed according to similar principles.

RCL Tear Location

Unlike UCL injuries, RCL injuries more commonly occur at the:

Proximal attachment.

Stener Equivalent

A true:

Stener lesion

does not occur with RCL rupture because the same interposition mechanism is:

Absent.

TMC Joint Injury

A stable TMC ligament injury may be treated with:

Immobilization.

Unstable TMC Joint

An acutely unstable TMC injury may require:

Reduction

and temporary:

Pin fixation.

Chronic TMC Instability

Chronic instability may require:

Ligament reconstruction

such as reconstruction of the:

Anterior oblique ligament

depending on the specific pattern.

Physical Therapy

Therapy is particularly important after:

Surgery.

Rehabilitation Goals

Treatment focuses on restoring:

Range of motion

Pinch strength

Grip strength

and safe progression back to:

Activity.

Internal Brace Rehabilitation

When ligament repair is augmented with a:

Suture-tape internal brace

selected patients may begin protected motion:

Earlier

than with traditional repair alone.

Medication

Pain can generally be managed with:

Acetaminophen

NSAIDs

or other short-term:

Nonopioid analgesia.

Natural Resolution of Pain

Even with appropriate immobilization, swelling and discomfort may persist for:

Several weeks.

Surgery

Acute MCP collateral ligament injuries that require surgery are usually treated with:

Direct suture repair.

Primary Repair

A complete acute tear can often be repaired directly to the:

Proximal phalanx

using:

Suture anchors

or

Bone tunnels.

Internal Brace

A:

Suture-tape internal brace

may be added to reinforce the repair and potentially permit:

Earlier rehabilitation.

Delayed Presentation

When diagnosis is delayed for approximately:

One month or longer

fibrosis and tissue retraction may make primary repair:

Difficult or impossible.

Reconstruction

Chronic injuries may require:

Local tendon advancement

Tendon graft

or

Fascial graft reconstruction.

Late Arthritis

Pain or crepitus during grinding of the MCP joint may indicate development of:

Posttraumatic arthritis.

MCP Arthrodesis

For painful advanced MCP arthritis with chronic instability:

Arthrodesis

may provide reliable:

Pain relief and stability.

TMC Arthritis

Chronic TMC injury complicated by advanced arthritis may be treated with procedures such as:

Arthrodesis

or

Trapeziectomy-based reconstruction

depending on the patient’s:

Age

Functional requirements

and

Arthritic pattern.

Follow-Up

After ligament repair or reconstruction, the thumb is commonly immobilized for approximately:

4–6 weeks.

Removable Splinting

After the initial healing phase, patients may transition to:

Removable splinting

with guided:

Range-of-motion exercises.

Strengthening

Progressive strengthening begins after sufficient:

Ligament healing

and restoration of:

Motion.

Return to Activity

Return to sport or unrestricted use is based on restoration of:

Stability

Strength

Motion

and

Pain-free function.

Prognosis

The prognosis after appropriate acute repair is generally:

Good to excellent.

Acute Injuries

Early recognition and treatment of complete UCL rupture provide the best chance for:

Stable healing

and restoration of:

Pinch strength.

Chronic Injuries

Chronic injuries can also achieve good outcomes after:

Reconstruction

although treatment is usually more technically:

Complex.

Complications

Potential complications include:

Chronic instability

Persistent pain

Nonunion of an avulsion fragment

and

Degenerative joint disease.

Chronic Instability

Untreated complete ligament rupture may result in persistent:

MCP laxity

and weak:

Pinch function.

Avulsion Nonunion

An avulsed bone fragment may fail to unite, leading to:

Pain

or persistent:

Instability.

Posttraumatic Arthritis

Longstanding joint incongruity or instability may cause:

Degenerative arthritis.

Surgical Complications

Other potential complications include:

Stiffness

Sensory nerve irritation

Recurrent instability

and

Repair failure.

Patient Monitoring

Follow-up should be performed by the:

Orthopaedic or hand surgeon

until healing and functional recovery are:

Complete.

Follow-Up Interval

Patients may be reviewed approximately every:

4–8 weeks

during the healing period.

Monitoring Goals

Assessment should include:

Joint stability

Range of motion

Pinch strength

Grip strength

and return to:

Normal activity.

Key Principle

Thumb ligament injuries most commonly involve the ulnar collateral ligament of the MCP joint, usually after forceful:

Thumb abduction.

Acute injury is termed:

Skier’s thumb, whereas chronic UCL insufficiency is historically called:

Gamekeeper’s thumb.

A complete tear is suggested by:

Marked instability and loss of a firm endpoint, while a:

Stener lesion

occurs when the avulsed UCL becomes trapped superficial to the adductor aponeurosis and therefore cannot heal normally.

Partial stable injuries are generally treated with:

Thumb-spica immobilization, whereas complete unstable tears and Stener lesions usually require:

Surgical repair.

Early recognition is important to prevent:

Chronic instability, weak pinch, and posttraumatic arthritis.