Mallet finger

Background

• Rupture of extensor tendon in area of distal phalanx distal to DIP joint
  • May be accompanied by avulsion fracture
• Caused by forced flexion of the DIP joint

Clinical Features

Finger in maximum extension

• Results in DIP joint flexed 40'
• Untreated leads to swan neck deformity
  • Flexed DIP
  • Hyperextended PIP

Differential Diagnosis

Hand and finger injuries

• Radiograph positive
  • Hand and finger fractures
  • Hand and finger dislocations
  • Triquetrolunate ligament instability
• Radiograph negative
  • Dupeytren contracture
  • Boutonniere deformity
  • Hand and finger tendon injuries
  • Ganglion cyst
  • De Quervain tenosynovitis
  • Intersection syndrome
  • Drummer's wrist
  • Extensor digitorum tenosynovitis
  • Vaughn Jackson syndrome
  • Snapping Extensor Carpi Ulnaris
  • Compressive neuropathy, "bracelet syndrome"
  • Scaphoid fracture
  • Osteoarthritis
  • Infiltrative tenosynovitis
  • Gout
  • Rheumatoid arthritis
  • Trigger finger
  • Mallet finger
    • Swan neck deformity
  • Jersey finger
  • Jammed finger
  • Subungual hematoma
  • Fingertip laceration
  • Metacarpophalangeal (MCP) ulnar ligament rupture (Gamekeeper's thumb)
  • Nail avulsion
  • High-pressure injection injury

Evaluation

Workup

Mallet finger without fracture

Mallet finger with fracture at the insertion of the extensor tendon

• Finger x-ray (PA and lateral)

Diagnosis

The injured digit will be often held in flexion with an inability to extend. The diagnosis is clinical although an avulsion fracture should also be ruled out.

Management

Special Mallet finger splint (if available)

• Splint DIP joint in continuous slight hyperextension x 6wk
• Splinting of the PIP joint is not necessary
• Give an extra splint

Disposition

• Hand surgery follow-up in 7-10 days

See Also

• Radiograph-Negative Hand and Finger Injuries

References

Authors

Ross Donaldson, Daniel Ostermayer, Allen Bookatz, Kevin Lu, Neil Young