Swan Neck Deformity 736.22

synonyms:

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

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

Swan Neck Deformity Follow-up Care

Swan Neck Deformity Review References  

• (Boyer MI, JAAOS 1999;7:92)