Orthopaedic Surgery - Phalanx Dislocation

Basics

Phalangeal dislocations involve disruption of the normal articulation of one of the joints of the hand.

They may involve the:

Metacarpophalangeal (MCP) joint

Proximal interphalangeal (PIP) joint

Distal interphalangeal (DIP) joint

Dislocations may occur alone or together with:

Fracture

Collateral ligament injury

Volar plate injury

Tendon disruption

Capsular injury

Classification is based primarily on:

The joint involved

and

The direction of displacement.

PIP Joint Dislocations

The PIP joint is the most commonly dislocated finger joint.

Dorsal PIP Dislocation

This is the:

Most common PIP dislocation.

It usually results from:

Hyperextension

with injury to the:

Volar plate.

The middle phalanx is displaced dorsally relative to the proximal phalanx.

Volar PIP Dislocation

Volar PIP dislocation is uncommon.

It usually results from:

Hyperflexion or rotational trauma

and is important because it may be associated with disruption of the:

Central slip of the extensor mechanism.

Failure to recognize central slip injury can later result in:

Boutonnière deformity.

Rotatory PIP Dislocation

Rotatory dislocations are rare.

They may occur when one condyle of the proximal phalanx:

Buttonholes between the central slip and lateral band of the extensor mechanism.

These injuries may be difficult to reduce by closed manipulation.

MCP Joint Dislocations

MCP dislocations may be:

Dorsal

Volar

or

Lateral.

Lateral MCP Dislocation

Lateral displacement is usually associated with:

Collateral ligament injury.

Dorsal MCP Dislocation

Dorsal MCP dislocation is associated with disruption of the:

Volar plate.

Some dorsal MCP dislocations are:

Complex and irreducible by closed means

because the volar plate or other soft tissue becomes interposed within the joint.

DIP Joint Dislocations

DIP dislocations are less common than PIP dislocations.

They are usually caused by:

Hyperextension trauma.

Simple DIP Dislocation

A simple dislocation can generally be:

Reduced with closed manipulation.

Complex DIP Dislocation

A complex dislocation cannot be reduced by closed means because of:

Soft-tissue or fracture-fragment interposition.

Entrapped structures may include the:

Volar plate

Flexor tendon

or other periarticular tissue.

Thumb MCP Injuries

Thumb MCP dislocation should be distinguished from:

Skier’s thumb or gamekeeper’s thumb, which refers specifically to an injury of the ulnar collateral ligament of the thumb MCP joint.

Dislocation may coexist with collateral ligament injury.

Prevention

Hand injuries in sports may be reduced by:

Appropriate coaching

Protective technique

Recognition of injury mechanisms

Prompt treatment after injury

In children’s sports, modifications such as softer equipment and appropriate size or weight categories may reduce injury risk in selected activities.

Epidemiology

Joint dislocations of the fingers occur most commonly in:

Skeletally mature adolescents and adults.

Pediatric Considerations

In younger children, the:

Growth plate is often weaker than the capsule and ligaments.

Therefore, a similar traumatic force may produce:

Physeal fracture or separation

rather than a true joint dislocation.

Incidence

PIP joint dislocations are relatively common in sports.

One study of NFL upper-extremity injuries reported that approximately:

17% involved PIP dislocations.

DIP dislocations are less common.

The most frequent pattern is:

Dorsal PIP dislocation.

Risk Factors

Activities associated with increased risk include:

Basketball

Football

Skiing

Ball sports

and other activities involving direct impact to an extended finger.

Genetics

There is no known Mendelian inheritance pattern associated with traumatic phalangeal dislocation.

Etiology

Trauma is the principal cause.

Dorsal Dislocation

Usually caused by:

Hyperextension.

This mechanism commonly disrupts the:

Volar plate.

Volar Dislocation

Usually caused by:

Hyperflexion

or rotational trauma.

Volar PIP injuries may damage the:

Central slip.

Rheumatoid Arthritis

Chronic inflammatory disease may also predispose to joint instability.

In rheumatoid arthritis, progressive damage can produce:

Volar plate insufficiency

PIP hyperextension

Swan-neck deformity

MCP volar subluxation

These are chronic deformities rather than typical acute traumatic dislocations.

Associated Conditions

Phalangeal dislocation may occur with:

Phalangeal fracture

Volar plate avulsion

Collateral ligament tear

Central slip injury

Flexor or extensor tendon injury

Small Avulsion Fragments

Small fracture fragments on radiographs are clinically important because they may represent:

Avulsion of a ligament, tendon, or volar plate attachment.

They should not be dismissed as incidental.

Diagnosis

Signs and Symptoms

Typical findings include:

Pain

Visible deformity

Swelling

Ecchymosis

Loss of motion

Neurovascular Symptoms

Marked displacement may compress digital neurovascular structures and cause:

Numbness

Paresthesia

Reduced perfusion

Although uncommon, these findings require urgent reduction.

History

Important details include:

Mechanism of injury

Direction of force

Time since injury

Any attempted reduction

Previous injuries to the digit

Hand dominance

Physical Examination

Neurovascular Status

Document before and after reduction:

Capillary refill

Digital sensation

Motor function when possible.

Skin Examination

Inspect carefully for:

Open wounds

Skin tenting

Lacerations

A small wound near a dislocated joint may indicate:

An open dislocation.

Deformity

The direction of displacement is often obvious on inspection.

The finger should be compared with the:

Contralateral side

when necessary.

Post-Reduction Examination

After reduction and once severe swelling subsides, reassess:

Joint stability

Collateral ligament integrity

Volar plate function

Tendon function

Range of motion

Central Slip Examination

After a volar PIP dislocation, evaluate specifically for:

Central slip injury

because missed disruption can progress to a:

Boutonnière deformity.

Imaging

Plain Radiographs

Initial radiographs should include:

AP

True lateral

Oblique views

These are necessary to evaluate:

Joint alignment

Fracture fragments

Articular involvement

Post-Reduction Radiographs

Radiographs should generally be repeated after reduction to confirm:

Concentric joint alignment

and identify:

Associated fractures that may not have been obvious initially.

Stress Views

Stress radiographs may occasionally help evaluate:

Collateral ligament insufficiency

after the joint has been reduced.

They are not routinely required for every injury.

Differential Diagnosis

Important alternatives and associated conditions include:

Fracture-dislocation

Chronic unreduced dislocation

Collateral ligament injury

Volar plate injury

Central slip injury

Rheumatoid deformity

Septic arthritis

Treatment

General Principles

The goals are to:

Restore joint congruity

Protect injured soft tissues

Minimize swelling

Begin motion early enough to avoid stiffness

Closed Reduction

Most simple dislocations can be treated with:

Closed reduction.

Reduction Technique

Reduction should be:

Gentle and controlled.

The joint is first:

Disimpacted with longitudinal traction

followed by controlled movement that reverses the mechanism of injury.

Forceful manipulation should be avoided because it can:

Entrap soft tissue

Create fracture

or

Worsen ligament or tendon damage.

Dorsal PIP Reduction

A typical dorsal PIP dislocation is reduced by:

Gentle traction

followed by:

Flexion of the middle phalanx over the proximal phalangeal head.

After Reduction

Once reduction is achieved:

Confirm stability

Repeat neurovascular examination

Obtain post-reduction radiographs

Control swelling

RICE Measures

Initial swelling control may include:

Rest

Ice

Compression

Elevation

Pediatric Patients

Children may require a somewhat longer period of initial protection because of:

Soft-tissue and physeal considerations.

Older protocols suggested immobilization for approximately:

7–10 days

after a stable reduction.

Prolonged immobilization should still be avoided when possible because finger joints stiffen quickly.

PIP Joint Treatment

Most stable dorsal PIP dislocations can begin:

Early range of motion

with or without:

Buddy taping.

Buddy Taping

Buddy taping is particularly useful for:

Stable collateral ligament injuries

and allows protected early motion.

Volar Plate Injury

A stable volar plate injury may be treated with an:

Extension-block splint

that prevents excessive extension while allowing controlled flexion.

Collateral Ligament Injury

Stable collateral ligament injuries are generally treated with:

Buddy taping

and early protected motion.

Complete Soft-Tissue Rupture

More substantial injuries involving complete disruption of:

Collateral ligaments

Volar plate

or

Central slip

may require a longer period of splinting, often:

Several weeks

depending on the structure involved and joint stability.

MCP Joint Immobilization

After reduction of a stable MCP dislocation, the joint is often protected in approximately:

50–70° of flexion.

The exact position depends on:

The joint

Direction of injury

Stability after reduction.

Central Slip Injury

Central slip injury requires specific protection.

The PIP joint is generally maintained in:

Full extension

while DIP motion is encouraged.

Older protocols often used approximately:

3 weeks of rigid extension splinting followed by dynamic splinting, although modern treatment commonly requires a longer continuous extension period depending on injury severity.

Physical Therapy

Hand therapy is important once joint stability is confirmed.

Treatment may include:

Active range-of-motion exercises

Gentle passive motion when safe

Edema control

Tendon-gliding exercises

Splint management

Importance of Early Motion

Finger joints, especially the PIP joint, develop stiffness rapidly.

Therefore, when the reduction is stable:

Early protected motion is preferred over prolonged immobilization.

Medication

Pain may be treated with:

Acetaminophen

or

NSAIDs

when appropriate.

Surgery

Surgery is indicated when:

Closed reduction fails

or when associated injuries require operative treatment.

Causes of Irreducibility

Closed reduction may fail because of:

Entrapped volar plate

Tendon interposition

Fracture fragment blocking reduction

Buttonholing of the phalanx through soft tissue

Operative Reduction

Both:

Volar

and

Dorsal approaches

may be used depending on the:

Joint involved

Direction of dislocation

Entrapped structure.

The joint is cleared and restored to:

Concentric alignment.

Associated Fracture Fixation

Surgery may also be necessary to stabilize:

Large articular fracture fragments

or

Unstable fracture-dislocations.

Open Injuries

Open dislocations require:

Irrigation

Debridement

Reduction

and treatment of associated:

Tendon, ligament, or fracture injury.

Thumb Ulnar Collateral Ligament Injury

A displaced complete thumb UCL tear may develop a:

Stener lesion, in which the torn ligament becomes trapped superficial to the adductor aponeurosis.

A Stener lesion generally requires:

Operative repair.

Referral

Early referral to a hand surgeon is appropriate for:

Irreducible dislocations

Open dislocations

Fracture-dislocations

Unstable injuries

Thumb MCP injuries with suspected complete UCL tear

Neurovascular compromise

Follow-Up

Patients should be reassessed to ensure:

Joint stability

Maintenance of reduction

Improvement in swelling

Preservation of motion

Prognosis

Most simple dislocations have a:

Good functional outcome

when reduced promptly and mobilized appropriately.

However, some degree of:

Residual swelling or loss of motion

is common, particularly at the:

PIP joint.

Persistent Swelling

PIP joint swelling may persist for:

Many months, occasionally up to a year after injury.

This does not necessarily indicate treatment failure.

Complications

Stiffness

The most common problem is:

Loss of motion, particularly after prolonged immobilization.

Recurrent Instability

Failure of ligament or volar plate healing may result in:

Chronic instability

or

Recurrent dislocation.

Chronic Deformity

Missed injuries can result in:

Swan-neck deformity

Boutonnière deformity

Flexion contracture

Neurovascular Injury

Digital nerve or vascular injury is uncommon but may occur in:

Severely displaced or open injuries.

Post-Traumatic Arthritis

Articular fracture or residual joint incongruity may eventually cause:

Post-traumatic osteoarthritis.

Patient Monitoring

Follow-up is usually performed every:

Several weeks during the early recovery period

to assess:

Range of motion

Stability

Pain

Swelling

Tendon function

Hand therapy may continue until adequate:

Motion and functional use

have returned.

Key Principle

Phalanx dislocations most commonly involve the PIP joint, with dorsal dislocation from hyperextension being the classic injury.

Management emphasizes:

Prompt closed reduction, careful assessment for associated fracture or tendon injury, and early protected motion once the joint is stable.

Irreducible, open, unstable, or fracture-associated dislocations require:

Early hand-surgical evaluation and, when necessary, operative reduction and repair.