Hand and finger tendon injuries

Background

The mucous sheaths of the tendons on the front of the wrist and digits. (Common sheath of Flexores digitorum subliminis and profundus labeled at center right.)

Tendons of the upper extremity anatomy

  • Fingers
    • FDP (DIP flexion)
    • FDS (PIP flexion)
    • Extensor dig communis (extension)
  • 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)

Clinical Features

  • Inability to move hand or finger in appropriate distribution

Differential Diagnosis

Hand and finger injuries

Evaluation

Flexor Zones

Flexor zones

Extensor Zones

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 fracture 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 with 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 antibiotic
  • Zone VI
    • Area over dorsum of hand
    • Tendons in this area are superficial; even minor-appearing lacs are associated with tendon injuries
    • Treatment typically requires operative fixation with 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

Management

Flexor

2-strand core suture technique for tendon repair.
  • Primary repair should occur within 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

Extensor

  • 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 is ok to refer to specialist within 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

Disposition

See Also

External Links

References