Swan neck deformity

Background

• Lateral bands displace proximally and dorsally = increased extension of PIP.
• FDP unopposed

Causes

• Rheumatoid arthritis
• Untreated mallet finger
• Laxity of the fibrous plate inside the hand at the base of the fingers or of the finger ligaments
• Spasticity from nerve damage
• Other arthritis
• Ruptured finger tendon
• Misalignment in the healing of middle phalanx fracture

Clinical Features

Multiple swan neck deformities from poorly controlled rheumatoid arthritis

• PIP extension with DIP flexion

Differential Diagnosis

• Joint volar subluxation
• FDS laceration
• Intrinsic contracture

Hand and finger injuries

• Distal finger
  • Finger amputation
  • Fingertip laceration
  • Nail avulsion
  • Nailbed laceration
  • Subungual hematoma
• Other finger/thumb
  • Boutonniere deformity
  • Mallet finger
    • Swan neck deformity
  • Jammed finger
  • Jersey finger
  • Trigger finger
  • Ring avulsion injury
  • De Quervain tenosynovitis
  • Infiltrative tenosynovitis
  • Metacarpophalangeal ulnar ligament rupture (Gamekeeper's thumb)
• Hand
  • Dupuytren contracture
• Wrist
  • Drummer's wrist
  • Ganglion cyst
  • Lunotriquetral ligament instability
  • Scaphoid fracture
  • Extensor digitorum tenosynovitis
  • Compressive neuropathy ("bracelet syndrome")
  • Intersection syndrome
  • Snapping Extensor Carpi Ulnaris
  • Vaughn Jackson syndrome
• General
  • Hand and finger dislocations
  • Hand and finger fractures
  • Hand and finger infections
  • Gout and pseudogout
  • Hand and finger tendon injuries
  • High-pressure injection injury
  • Osteoarthritis
  • Rheumatoid arthritis
  • Ring removal

Evaluation

• Clinical diagnosis
• Consider x-ray to rule out avulsion fracture

Management

• Extension block splint
• Refer to orthopedic surgery

Disposition

• Discharge

See Also

• Hand and finger diagnoses
• Hand and finger tendon injuries