Flexor Tendon Laceration Assessment and Repair

Algorithm Steps

1. ▶

   Start

   Suspected Flexor Tendon Laceration

   Hand/finger laceration with weakness

   1. ●

      Action

      History and Examination

      Assess mechanism and function

      • HISTORY:
      • - Mechanism (sharp vs crush)
      • - Time since injury
      • - Hand dominance
      • - Occupation/hobbies
      • EXAMINATION:
      • - Wound location (predict zone)
      • - Active finger flexion
      • - Cascade (resting posture)
      • - Neurovascular status
      1. ●

         Action

         Test FDS Function

         Flexor digitorum superficialis

         • Hold adjacent fingers in extension
         • Ask patient to flex PIP joint
         • FDS intact: Can flex PIP independently
         • FDS cut: Cannot flex PIP alone
         • Note: Little finger FDS often absent/weak
         1. ●

            Action

            Flexor Tendon Zones

            Verdan classification

            • ZONE I: Distal to FDS insertion
            • - Only FDP present
            • ZONE II: 'No Man's Land' (A1 pulley to FDS insertion)
            • - FDP + FDS in tight sheath
            • - Historically worst outcomes
            • ZONE III: Palm (lumbrical origin to A1)
            • - FDP + FDS, more space
            • ZONE IV: Carpal tunnel
            • - Tendons + median nerve
            • ZONE V: Wrist to forearm
            • - Muscle-tendon junction
            1. ◆

               Decision

               Partial vs Complete Laceration?

               Affects management

               • <50% transected: May not need repair
               • >50-60% transected: Repair recommended
               1. ●

                  Action

                  Partial Laceration (<50%)

                  Conservative vs repair

                  • Options:
                  • - Trim frayed edges, no repair
                  • - Epitendinous repair only
                  • - Splint and early motion
                  • Watch for triggering
                  • Repair if >50-60% involved
                  1. ●

                     Action

                     Postoperative Protocol

                     Rehabilitation critical

                     • SPLINTING:
                     • - Dorsal blocking splint
                     • - Wrist 20° flexion, MCP 70° flexion
                     • - IP joints extended
                     • EARLY MOTION PROTOCOLS:
                     • - Passive flexion, active extension
                     • - Place and hold (Duran/Kleinert)
                     • - True active motion (selected cases)
                     • PROGRESSION:
                     • - 4-6 weeks: Begin active flexion
                     • - 8-12 weeks: Resistance
                     • - 3-4 months: Return to activities
                     1. ●

                        Action

                        Complications

                        Watch for

                        • RUPTURE: 2-5%
                        • - Usually 10-21 days postop
                        • - Need revision repair/graft
                        • ADHESIONS: Most common
                        • - Limits tendon gliding
                        • - May need tenolysis
                        • STIFFNESS:
                        • - PIP contracture common
                        • - Therapy essential
                        • SWAN NECK (Zone I):
                        • - From FDP scarring
                        1. ✓

                           Outcome

                           Outcomes

                           Expected results

                           • Zone II: 75-90% good/excellent
                           • Modern multi-strand repairs improved outcomes
                           • Early active motion protocols help
                           • Measure: Total active motion (TAM)
                           • Excellent: >75% normal TAM
                           • Good: 50-75% normal TAM
               2. ●

                  Action

                  Timing of Repair

                  When to operate

                  • PRIMARY (<24h): Ideal if clean
                  • DELAYED PRIMARY (1-14 days): Acceptable
                  • SECONDARY (>3-4 weeks): More difficult
                  • LATE (>6 weeks): May need graft/staged
                  • FACTORS:
                  • - Wound contamination
                  • - Associated injuries
                  • - OR availability
                  1. ●

                     Action

                     Surgical Repair Principles

                     Modern technique

                     • APPROACH:
                     • - Bruner incisions for exposure
                     • - Preserve pulleys (especially A2, A4)
                     • CORE SUTURE:
                     • - Multi-strand technique (4-6 strand)
                     • - Stronger = earlier motion
                     • - Kessler, Cruciate, Tang techniques
                     • EPITENDINOUS SUTURE:
                     • - 5-0 or 6-0 running/simple
                     • - Smooths repair, adds strength
                     • FDS REPAIR:
                     • - Zone II: Repair one slip if tight
                     • - May excise both slips if needed
      2. ●

         Action

         Test FDP Function

         Flexor digitorum profundus

         • Stabilize PIP joint in extension
         • Ask patient to flex DIP joint
         • FDP intact: Can flex DIP
         • FDP cut: Cannot flex DIP
         • Always test thumb FPL separately