What is the treatment approach for swan neck deformity?

Treatment Approach for Swan Neck Deformity

The most effective treatment for swan neck deformity is surgical correction using tenodesis techniques, with the Littler procedure (oblique retinacular ligament reconstruction) showing excellent outcomes for rheumatoid-related cases and distal interphalangeal joint fusion being most reliable for post-traumatic cases. 1, 2

Understanding Swan Neck Deformity

Swan neck deformity is characterized by:

• Hyperextension of the proximal interphalangeal (PIP) joint 1
• Flexion of the distal interphalangeal (DIP) joint 1
• May be caused by rheumatoid arthritis, trauma (particularly after mallet finger injuries), cerebral palsy, or Ehlers-Danlos syndrome 1, 2, 3

Assessment and Classification

Before determining treatment, proper assessment is essential:

• Classify the deformity according to severity (Nalebuff stages I-III for rheumatoid cases) 1
  • Stage I: Dynamic (passively correctable)
  • Stage II: Partially contracted
  • Stage III: Fixed contracture
• Radiographic evaluation to assess joint integrity (Larsen staging for rheumatoid cases) 1
• Determine if the deformity is of articular origin 1

Treatment Algorithm

Conservative Management

• For mild, flexible deformities:
  • Custom splinting to prevent PIP hyperextension while allowing flexion 4
  • Hand therapy to maintain joint range of motion 4

Surgical Management

Based on etiology and severity:

For Rheumatoid Arthritis-Related Swan Neck Deformity:

1. Littler Procedure (ORL reconstruction) - First-line surgical option for Nalebuff stages I-III 1

   • One lateral band is sectioned proximally and transposed palmarly
   • The band is passed under the Cleland ligament and sutured to the A2 pulley
   • Creates a tenodesis effect that prevents PIP hyperextension while maintaining DIP extension
   • Outcomes: Converts average PIP hyperextension of 21° to 24° of flexion 1

2. Combined Lateral Band and FDS Techniques

   • Combines Littler's lateral band technique with Zancolli's FDS-palmar plate pulley 5
   • Provides stable correction with no recurrence in follow-up averaging 20 months 5
   • Converts average PIP hyperextension of -13.3° to +13.4° 5

For Post-Traumatic Swan Neck Deformity (following mallet finger):

1. DIPJ Arthrodesis (Fusion) - Most reliable solution 2

   • Preferred for chronic cases with established deformity
   • 64% of cases in recent study required this approach 2

2. DIPJ Pinning - Alternative for less severe cases 2

   • Used in 32% of cases in recent studies 2

3. Superficialis Sling (FDS Tenodesis) - Option for various etiologies 3

   • Creates a static volar restraint against PIP hyperextension
   • Various techniques for securing the FDS slip:
     • Tunneling through proximal phalanx bone
     • Attaching to A1 or A2 pulley
     • Securing with bone anchors 3

Postoperative Management

• Immediate postoperative mobilization for PIP flexion 1
• Figure-of-eight splint worn for 12 weeks 1
• Splint should allow full PIP flexion but limit extension to 20-30° of flexion 1
• For cases requiring temporary transfixation, wire removal after 4-6 weeks 1
• Passive extension beyond 20-30° only after 12 weeks 1

Complications and Outcomes

• Overall complication rate of 50% for post-traumatic cases 2
• Major complications in 33% of surgeries for post-traumatic cases 2
• Reoperation rate of 33% for post-traumatic cases 2
• For rheumatoid cases using the Littler procedure:
  • No complications or recurrence in one study with 22-month follow-up 1
  • Pain reduction in nearly all patients 1
  • Maintained radiologic joint status 1

Special Considerations

• Surgery should be performed by surgeons with expertise in hand deformities 4
• For pediatric patients with congenital hand deformities, referral to a pediatric plastic surgeon or pediatric orthopedic surgeon is recommended 4, 6
• Regular follow-up is essential to monitor for recurrence or progression of deformity 4