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  • Volar plate injury
  • Duck bill deformity
  • Recurvatum deformity

  • 736.22 Swan-neck deformity

  • M20.03 Swan-neck deformity
  • M20.031 Swan-neck deformity of right finger(s)
  • M20.032 Swan-neck deformity of left finger(s)
  • M20.039 Swan-neck deformity of unspecified finger(s)


  • Injury or loosening of the volar plate (ligament connecting proximal and middle phalanx that prevents hyperextension of the PIP)
  • Hyperextension of the proximal interphalangeal joint (PIP) and flexion of the distal interphalangeal joint (DIP)
  • Duck bill deformity is the same issue in the thumb less one joint

Essentials of Diagnosis

  • Rheumatoid arthritis (RA)—most common cause of swan neck deformity
  • Chronic inflammation loosens the volar plate, making PIP susceptible to hyperextension
  • As a result, extensor tendon tightens causing DIP to pull into flexed position
  • Swan neck classification4
    • I: PIP joint flexible in all positions
    • II: PIP motion limited only by tenodesis effect
    • III: fixed PIP joint contracture, x-ray okay
    • IV: x-ray shows arthritic changes

General Considerations

  • Pain and swelling of the PIP
  • Can be managed surgically or non-surgically depending upon signs and symptom severity, response to conservative treatment, and orthopedic physician recommendations
  • Other causes include trauma, nerve injury such as cerebral palsy, Parkinson’s disease, or stroke.


  • Adults
  • 50% of population with RA4
  • Associated with population with neurological disorders (cerebral palsy, Parkinson’s disease, CVA)

Signs and Symptoms

  • Pain and swelling of the PIP joint
  • Laxity of the volar plate
  • Snapping and locking of the fingers
  • Hyperextension of the PIP and flexion of the DIP

Functional Implications

  • Difficulty and or pain with opening and closing hand in preparation for grasping or reaching
  • Difficulty and/or pain with grasping dishes, utensils, or drinking cups due to pain and weakness
  • Difficulty and/or pain with grasping and turning steering wheel
  • Difficulty and/or pain with turning doorknob

Possible Contributing Causes

  • Trauma
  • Rheumatoid arthritis, or other rheumatic or connective tissue disorders
  • Neurological disorders
  • Cerebral palsy
  • Parkinson’s disease
  • Ehlers-Danlos syndrome
  • Untreated mallet finger
  • Overuse of the hand and fingers

Differential Diagnosis

  • Ganglion of tendon sheath
  • Dupuytren disease
  • Loose body in the MCP joint
  • Subluxation of the extensor digitorum communis


  • X-ray to rule out fracture.


  • NSAIDs

Medical Procedures

  • Surgical options possible after failed conservative care
  • Soft tissue repair
  • PIP arthroplasty (PIP replaced with metal implant)
  • Interphalangeal arthrodesis

  • Radiologist for imaging, x-ray to rule out other pathology
  • Primary care to rule our rheumatic causes ...

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