Swan Neck Deformity M20.039 736.22

swan-neck deformity 
ICD-9 Classification / Treatment
Etiology / Natural History Associated Injuries / DDx
Anatomy Complications
Clinical Evaluation Follow-up Care
Xray / Diagnositc Tests Review References


Swan Neck Deformity ICD-10

Swan Neck Deformity ICD-9

  • 736.22 Swan Neck Deformity 736.22

Swan Neck Deformity Etiology / Epidemiology / Natural History

  • Characterized by hyperextension of the PIP joint and flexion of the DIP joint 
  • Affects approximately 14% of patients with established rheumatoid arthritis (Boyer MI, JAAOS 1999;7:92)
  • Generally caused by tenosynovitis and synovitis in the finger and PIP joint

Swan Neck Deformity Anatomy

  •  The volar plate, collateral ligaments, and flexor digitorum superficialis allows the PIP joint to hyperextend due to extensor mechanism forces.  The deforming forces may be accentuated by intrinsic contracture/tightness related to MCP joint flexion and volar subluxation.
  • DIP joint synovitis may rupture the terminal extensor tendon which worsens the PIP hyperextention

Swan Neck Deformity Clinical Evaluation

  •  hyperextension of the PIP joint with concomitant flexion of the DIP joint

Swan Neck Deformity Xray / Diagnositc Tests


Swan Neck Deformity Classification / Treatment

  •  Nalebuff Type I: flexible hyperextension of the PIP joint.  RX: 
  • Nalebuff Type II: tightness of the intrinsic muscles causes limitation of PIP joint flexion when the MCP joint is maintained in extension.
  • Nalebuff Type III: limited PIP joint flexion in all MCP joint positions due to the inability of the lateral bands to translate volar to the axis of rotation of the PIP joint.
  • Nalebuff Type IV: destruction of the articular surface of the PIP joint
  • Treatment options: see (Boyer MI, JAAOS 1999;7:92)

Swan Neck Deformity Associated Injuries / Differential Diagnosis


Swan Neck Deformity Complications

  • Boyer MI, JAAOS 1999;7:92

Swan Neck Deformity Follow-up Care


Swan Neck Deformity Review References