Principles of Tendon Repair

Injury Retraction

  • Determined by posture of hand at time of injury
  • Flexed → retraction of distal tendon
  • Extended → retraction of proximal tendon

Healing Stages

  1. Inflammation

    • 0-5 days
    • Cellular inflammatory cascade

  2. Proliferation

    • 5-28 days
    • Collagen formed by fibroblasts

  3. Remodeling

    > 28 days
    • New collagen fibers cross-link and remodel

Mobilization & Healing

  • Mobilization of the tendons improves the healing response
  • At 3 weeks, a mobilized tendon is twice as strong as an immobile tendon

Goals of Tendon Repair

  • Restore function of the tendon by minimizing adhesions, maximizing strength and glide, and preventing complications
  • Achieved by:
    • Strong sutures
    • Gap-resistant techniques
    • Early mobilization (especially flexors)
    • No-touch technique

Sutures

  • Non-Absorbable on an atraumatic, non-cutting needle (Size 3-0)
  • Unbraided: Slides easily through tendon
  • Braided: Prevents late gapping as it has less elasticity

Core Suture

  • Modified Kessler x2
  • Four-strand core suture: 2x stronger than a two-strand technique
  • Six-strand suture: 3x stronger but difficult to perform

Epitendinous Suture

  • Silverskold (running suture) or horizontal mattress
  • Epitendinous repair adds 20-40% strength to core repair

Technical Tips

  • Plan skin incisions
  • Use Brunner’s incision preserving A2 & A4 pulleys
  • Retrieve tendon down sheath using an umbilical catheter trick
  • Transfix tendons with needles during suturing (tension-free repair)
  • Place posterior epitendinous sutures before core stitch
  • Avoid bunching up of the tendon – ensure good gliding

Flexor Tendon Rehabilitation

  • Children & non-compliant patients → immobilized for 4 weeks
  • All others → early motion initiated
    • Stronger tendon within 3 weeks
    • Fewer adhesions

Early Active Motion

  • E.g., Belfast Protocol (newer vogue)
  • Requires a strong repair
  • Moderate force
  • Potential to increase excursion & reduce adhesions
  • Extension blocking splint (wrist and MCPJ flexed)
  • Marginally higher re-rupture but less adhesions

Passive Motion Protocols

  • Traditional approach (~6 weeks)

Kleinhert Protocol

  • Low force & low excursion
  • Active extension and passive flexion
  • Flexion via dynamic splint (not patient-controlled)
  • Marginally lower re-rupture rate
  • More adhesions
  • Difficult setup (elastic bands required)

Duran Protocol

  • Low force & low excursion
  • Active extension and passive flexion
  • Patient performed
  • Requires good patient compliance

Complications

  • Infection
  • Re-rupture (5-10%)
  • Stiffness (most common in Zone 2)
  • CRPS
  • NV injury

Principles of Delayed Repair (>3 Weeks)

  • Primary repair unlikely to succeed due to:
    • Retracted tendon
    • Avascularity (due to tenuous vincular supply)
    • Scarred sheath
  • Tendon reconstruction is the best option

Tendon Grafting

Prerequisites

  • Full passive motion must be present
  • Neurovascularly intact fingers

Single vs. Two-Stage Repair

  • Single-stage
    • Faster recovery
    • Higher risk of adhesions & failure
    • Possible in early delayed period
  • Two-stage
    • 1st Stage:
      • Restore passive ROM (physio, MUA)
      • Tenolysis & contracture release
      • Repair vessels & nerves if needed
      • Recannulate sheath & pulleys with a silastic rod
    • 2nd Stage:
      • Remove rod & use tendon graft (2-3 months later)

Graft Options

  • Palmaris longus
  • Plantaris
  • Toe Extensors
  • Extensor Indicis Proprius (EIP)
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