What is the treatment for a small avulsion fracture at the base of the thumb interphalangeal joint?

Treatment of Small Avulsion Fracture at the Base of the Thumb Interphalangeal Joint

For a small avulsion fracture at the base of the thumb interphalangeal joint, conservative treatment with rigid immobilization (casting or splinting) for 3-6 weeks is recommended as first-line treatment, provided the fracture is minimally displaced (<2-3mm) and the joint remains stable. 1

Initial Assessment and Imaging

• Radiography is always indicated as the initial imaging for suspected thumb fractures, with at least 2 views recommended (PA and lateral), though adding an oblique view increases diagnostic yield 1
• For thumb fractures specifically, radiographs should assess:
  • Displacement of the fracture fragment (>3mm indicates need for surgery) 1
  • Articular involvement (>1/3 of articular surface indicates need for surgery) 1
  • Rotation of the fragment (may prevent healing even with immobilization) 2
  • Joint stability (unstable joints require surgical intervention) 3

Treatment Algorithm

Conservative Management (First-line for stable, minimally displaced fractures)

• Rigid immobilization with a thumb spica cast or splint for 3-6 weeks is indicated for:

  • Minimally displaced fractures (<2-3mm) 1, 3
  • No significant rotation of the fragment 2
  • Stable joint on examination 3

• Follow-up radiographs should be obtained at 10-14 days to ensure the fracture position is maintained 1

• After immobilization period:

  • Transition to buddy taping and begin active range of motion exercises 4
  • Continue protective buddy taping for up to 6 weeks total 4

Surgical Management (For unstable or significantly displaced fractures)

• Surgery should be considered when:

  • Fracture fragment displacement >3mm [1, @16@]
  • Significant rotation of the fragment is present (even with minimal displacement) 2
  • Joint instability is demonstrated on examination 3
  • Involvement of more than one-third of the articular surface 1
  • Conservative treatment has failed to provide pain relief or restore function 1

• Surgical options include:

  • Open reduction and internal fixation using:
    • Hook plate technique for small fragments (provides stable fixation allowing early active motion) 5
    • Tension wire fixation (effective for small fragment sizes) 6

Outcomes and Prognosis

• With appropriate treatment, most patients can expect:
  • Good to excellent functional outcomes 5, 6
  • Return to normal grip and pinch strength (90-97% of uninjured side) 6, 3
  • Near-normal range of motion of the thumb joints 6

Important Caveats and Pitfalls

• Even minimally displaced avulsion fractures may have significant rotation that prevents successful healing with cast immobilization alone 2

• Failure to identify and properly treat these fractures can lead to:

  • Persistent thumb pain, especially with activities requiring strong pinch 2
  • Decreased pinch strength 2
  • Joint instability 3
  • Need for delayed surgical intervention 2

• Post-treatment monitoring should be adapted to the patient's individual needs, with particular attention to:

  • Pain relief 1
  • Restoration of function 1
  • Joint stability 3