Mallet tenodesis

Mallet Finger Injury – Tenodesis Procedure

Indications

• Chronic mallet finger deformity with extensor lag (>6 weeks old)
• Failed conservative management with splinting
• Soft tissue loss or tendon retraction preventing direct repair
• Mallet finger with swan-neck deformity
• Functional impairment due to drooping of the distal phalanx

Contraindications

• Acute mallet finger without trial of conservative treatment
• Severe arthritis or joint destruction
• Poor soft tissue coverage (e.g., infection, open wounds)
• Severe stiffness of the distal interphalangeal joint (DIPJ)
• Noncompliant patient unwilling to adhere to postoperative immobilization

Preoperative Preparation

• Imaging: AP and lateral X-rays to assess joint congruency and rule out fractures
• Patient counseling: Explain risks, benefits, and need for postoperative immobilization
• Medical optimization: Control diabetes if present, optimize vascular status if needed
• Anesthesia planning: Local or regional block with sedation preferred

Special Instruments, Position, and Anesthesia

• Special Instruments:
  • Small tendon sutures (4-0 or 5-0 non-absorbable)
  • Bone anchor or drill for tendon fixation (if required)
  • K-wires for temporary DIPJ fixation (if needed)
  • Microsurgical instruments for tendon handling
• Positioning:
  • Supine with hand placed on a hand table
  • Arm tourniquet to minimize bleeding (optional)
• Anesthesia:
  • Local anesthesia with epinephrine for hemostasis
  • Alternatively, regional block (brachial plexus or digital block)

Operative Technique & Approach in Detail

1. Incision & Exposure:
   • Dorsal midline or slightly lateral incision over DIPJ
   • Preserve dorsal skin flaps for better healing
2. Identification of Extensor Mechanism:
   • Dissect to expose the extensor tendon
   • Identify the retracted tendon ends
3. Tendon Mobilization & Tenodesis Preparation:
   • If tendon is retracted proximally, mobilize it
   • If needed, release adhesions and scar tissue
4. Tenodesis Technique:
   • Direct Repair (If Possible): End-to-end repair with non-absorbable sutures
   • Bone Anchor Tenodesis: Drill a small hole in the distal phalanx, pass the tendon, and fix with an anchor or sutures through the bone
   • K-wire Fixation (If Required): If extensor lag remains, temporary DIPJ extension with K-wire for 4-6 weeks
5. Closure & Dressing:
   • Skin closure with fine sutures
   • Sterile dressing with mild compression
   • Splinting in slight hyperextension

Tips and Pearls

• Ensure DIPJ is not over-tightened to avoid hyperextension deformity
• Use a fine, non-absorbable suture for tendon repair to minimize bulk
• If tendon is severely shortened, consider tendon grafting (e.g., palmaris longus)
• Temporary K-wire stabilization can improve healing in cases with poor tendon quality

What to Avoid

• Overtightening the repair: Leads to permanent DIP hyperextension
• Inadequate fixation: Risk of repair failure or recurrent drooping
• Neglecting soft tissue coverage: Leads to poor healing and infection
• Failure to address swan-neck deformity: Can lead to persistent functional issues

Postoperative Care Issues

• Splinting: Maintain DIPJ in slight extension for 6-8 weeks
• Wound care: Regular dressing changes, avoid tension on the wound
• Rehabilitation: Gradual mobilization after 6-8 weeks, with night splinting
• Complications to monitor:
  • Infection
  • Skin necrosis from tight splinting
  • Extensor lag recurrence
  • Joint stiffness
• Return to activity: Light use at 8 weeks, full activity after 12 weeks