What is the treatment for swan neck deformity?

Treatment of Swan Neck Deformity

The treatment of swan neck deformity should focus on splinting as first-line therapy, followed by surgical intervention for refractory cases, with the specific approach determined by the severity and flexibility of the deformity. Swan neck deformity is characterized by hyperextension of the proximal interphalangeal (PIP) joint with flexion of the distal interphalangeal (DIP) joint, affecting both hand function and appearance.

Assessment and Classification

Before initiating treatment, assess:

• Flexibility of the deformity (passively correctable vs. fixed)
• Severity using Nalebuff classification:
  • Stage I: Dynamic (fully correctable)
  • Stage II: Partially contracted
  • Stage III: Contracted (fixed)
• Underlying cause (rheumatoid arthritis, trauma, hypermobility, etc.)
• Impact on hand function and activities of daily living

Non-Surgical Management

Splinting

• First-line treatment for flexible deformities
• Custom-made orthoses are preferred over prefabricated ones for better compliance and outcomes 1
• Options include:
  • Silver ring splints
  • Figure-of-eight finger splints
  • PIP blocking splints that limit hyperextension while allowing flexion

Physical Therapy

• Focus on:
  • Range of motion exercises
  • Strengthening of intrinsic and extrinsic hand muscles
  • Joint protection principles and ergonomics 1
  • Hand function training

Surgical Management

Surgical intervention is indicated when:

• Conservative treatment fails
• Deformity significantly impacts hand function
• Patient has adequate motivation for postoperative rehabilitation

Surgical Options Based on Deformity Stage

For Flexible Deformities (Nalebuff Stage I)

• Tenodesis procedures:
  • Littler's oblique retinacular ligament (ORL) reconstruction: One lateral band is sectioned proximally, passed underneath the Cleland ligament, and sutured to the A2 pulley 2
  • Half flexor digitorum superficialis (FDS) tenodesis: Using half of the superficialis flexor tendon sutured to the A2 pulley through a volar approach 3

For Partially Contracted Deformities (Nalebuff Stage II)

• Combination of soft tissue procedures:
  • Volar plate plication of PIP joint
  • Hemitenodesis of ulnar slip of FDS tendon 4
  • May require dorsal arthrolysis

For Fixed Deformities (Nalebuff Stage III)

• More extensive procedures:
  • PIP joint arthrodesis in functional position
  • DIP joint fusion when associated with chronic mallet finger 5
  • Extra-articular subcutaneous ligament reconstruction using artificial ligaments in severe cases 6

Postoperative Management

• Immediate postoperative mobilization for PIP flexion
• Figure-of-eight splint worn for 12 weeks
• Splint should allow full PIP flexion but limit extension to 20-30° of flexion
• For temporary transfixation cases, wire removal after 4-6 weeks followed by mobilization 2
• Passive extension beyond 20-30° of flexion only after 12 weeks

Outcomes and Complications

• Surgical correction can significantly improve hand function and appearance
• Success rates vary by technique:
  • Littler tenodesis shows good results with reduction of hyperextension and improved flexion 2
  • Half FDS tenodesis demonstrates good long-term results with PIP flexion gains of approximately 26° 3
• Potential complications:
  • Recurrence of deformity
  • Inadequate correction
  • PIP joint stiffness
  • Tendon rupture
  • Need for reoperation (reported in up to 33% of cases) 5

Special Considerations

• In rheumatoid arthritis, address underlying disease with appropriate medical management
• For post-traumatic cases, especially following mallet finger injuries, DIPJ fusion appears to provide the most reliable solution 5
• In hypermobility syndromes, combined surgical and splinting approaches may be necessary 4

Early intervention is crucial to prevent progression to fixed deformity, which is more difficult to treat and has less favorable outcomes in terms of hand function and patient satisfaction.