Hand and finger tendon injuries

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Tendons of the upper extremity anatomy

  • Fingers
    • FDP (DIP flexion)
    • FDS (PIP flexion)
    • Extensor dig communis (extension)
      • Mallet = DIP
      • Boutonniere = PIP
  • Thumb
    • Flx pollicis longus (flexion)
    • Ex poll longus (DIP ext)
    • Ex poll brevis (MCP ext)
    • Abductor poll longus (abduction)
  • Wrist
    • Flexor carpi ulnaris (flx + ulnar deviation)
    • Flexor carpi radialis (flx + radial dev)
    • Extensor carpi ulnaris (ext + ulnar dev)
    • Extensor carpi radialis (ext + radial dev)



Flexor zones


  • Primary repair should occur w/in 12hr; secondary repair can occur up to 4wk after injury
  • Hand surgeon should repair all flexor tendon lacerations
  • If hand surgeon is not immediately available:
    • Irrigate open wounds and close with 5-0 nylon
    • Most advocate antibiotics
    • Splint hand with:
      • Wrist in 30 deg of flexion
      • MCP joints in 70 deg of flexion
      • IP joint flexed 10-15 deg of flexion



  • Most common site of tendon injuries b/c of superfical location on dorsum of hand
  • If tendon lac suspected but unable to be located it's ok to refer to specialist w/in 3d
    • Delayed repair up to 7-10d usually has equal outcome to immediate repair
  • Zones V-VII Splinting (after repair)
    • Requires splinting with:
      • Wrist in 15 deg extension
      • MCP joint in 15 deg flexion
      • IP join in 15 deg flexion in involved and adjacent digit


Extensor zones
  • Zone I
    • Area over distal phalanx and DIP joint
    • Complete laceration at this level will result in DIP joint flexed 40 degrees
    • "Mallet finger" refers to closed disruption of distal extensor apparatus
      • Occurs due to sudden forceful flexion of extended finger (finger gets "jammed")
      • May occur due to tear of tendon itself or avultion fx of dorsal base of phalanx
      • Most common tendon injury in athletes
    • Immobilize DIP joint only in continuous slight hyperextension for 6-8wks
  • Zone II
    • Area over middle phalanx
    • Treatment is similar to zone I injuries
  • Zone III
    • Area over the PIP joint
    • Central tendon is most commonly injured structure
    • Controversial whether conservative or operative management is best
      • Closed injuries are initially treated w/ PIP joint immobilized in extension for 5-6wks
      • Must be followed closely by hand specialist
  • Zone IV
    • Involves area over proximal phalanx
    • Clinical findings are similar to zone III injuries
  • Zone V
    • Area over MCP joint
    • Open injuries to this area should be considered human bites until proven otherwise
      • If it is human bite performed delayed repair following course of abx
  • Zone VI
    • Area over dorsum of hand
    • Tendons in this area are superficial; even minor-appearing lacs are a/w tendon injuries
    • Treatment typically requires operative fixation w/ K wires
  • Zone VII
    • Area over the wrist
    • Repair can be difficult because of presence of extensor retinaculum
  • Zone VIII
    • Area of the distal forearm
    • Tendons frequently retract into the forearm and must be retrieved and repaired
    • Lac <25%: does not require repair
    • Lac 25-50% requires simple suture repair
    • Lac >50% requires specialized repair

See Also