What is the treatment for a thumb dislocation?

Treatment of Thumb Dislocation

Thumb dislocations require immediate closed reduction followed by thumb spica immobilization for 3-6 weeks, but surgical intervention is mandatory when the joint remains unstable after reduction, when fracture fragments are displaced >3mm, or when more than one-third of the articular surface is involved. 1, 2

Initial Diagnostic Workup

• Obtain at least 2-view radiographs (PA and lateral) immediately to assess for associated fractures, fragment displacement, and articular involvement 1, 2
• Adding an oblique view increases diagnostic yield for thumb injuries 2
• Specifically evaluate for fracture fragment displacement >3mm and involvement of >1/3 of the articular surface, as these findings mandate surgical treatment 1, 2

Treatment Algorithm Based on Joint Stability and Fracture Pattern

Stable Dislocations Without Significant Fracture

• Perform closed reduction and immobilize with thumb spica cast or splint for 3-6 weeks 1, 2
• Obtain follow-up radiographs at 10-14 days to confirm maintained reduction 2
• This approach is appropriate for minimally displaced fractures (<2-3mm) 2

Unstable Dislocations or Failed Closed Reduction

Surgical intervention is required in the following scenarios:

• Fracture fragment displacement >3mm 1, 2
• Involvement of more than one-third of the articular surface 1, 2
• Joint instability after attempted closed reduction due to severe collateral ligament disruption 3
• Interposition of soft tissue structures (extensor tendons, volar plate, or flexor pollicis longus) blocking reduction 3, 4, 5

Critical Anatomic Considerations by Location

Metacarpophalangeal (MP) Joint Dislocations

• Palmar dislocations are classified into three types: Type A (stable joint without severe ligament injury), Type B (tendon interposition preventing reduction), and Type C (joint instability from severe collateral ligament disruption) 3
• Type B is the most common pattern and requires surgical treatment due to extensor tendon interposition 3
• Patients with severe collateral ligament disruption require open reduction and ligament repair 3

Interphalangeal (IP) Joint Dislocations

• These are less common due to inherent joint stability 5
• Irreducible dislocations are typically caused by volar plate avulsion or displaced flexor pollicis longus tendon blocking reduction 4, 5
• Percutaneous or open reduction techniques may be needed to reposition interposed structures 5

Common Pitfalls to Avoid

• Do not assume all dislocations are reducible by closed means – failed closed reduction attempts indicate soft tissue interposition requiring surgical intervention 3, 4
• Do not miss associated ligamentous injuries – even after successful reduction, severe collateral ligament disruption causes persistent instability requiring surgical repair 3
• Do not underestimate small avulsion fractures – fragments involving >1/3 of the articular surface require surgical fixation regardless of size 1, 2
• Always obtain follow-up radiographs at 10-14 days to ensure maintained reduction, as late displacement can occur 2

Post-Reduction Management

• Immobilize with thumb spica cast or splint for 3-6 weeks following successful reduction 1, 2
• Monitor for pain relief and restoration of function as key outcome measures 1, 2
• Adapt follow-up frequency to individual patient needs, with particular attention to functional recovery 2