II. Anatomy: Dorsal Hand Zones (Extensor Hand)
- Zone 1: DIP Joint and Distal Phalanx (including Fingernail)
- Zone 2: Middle Phalanx
- Zone 3: PIP Joint and Proximal Phalanx
- Zone 4: MCP Joint
- Zone 5: Distal Metacarpals
- Zone 6: Proxmal Metacarpals
- Zone 7: Distal wrist and Carpal Bones
- Zone 8: Proximal wrist and Carpal Bones
III. Signs
- Variable loss of active finger extension
- Inspect all Lacerations for Tendon Injury
-
Metacarpal-phalangeal joint (MCP) may be most difficult
- Tendon retracts most at this location
- Exploration may require Laceration extension
- Allows for tendon visualization
IV. Imaging
- XRay Hand Indications
- Evaluate for Retained Foreign Body (Radiopaque Foreign Body)
- Concurrent Fractures
- Joint injury
V. Management: Repair
- Open Extensor Tendon Lacerations are amenable to Emergency department repair
- Contrast with flexor tendon injuries which are made more complicated by anatomy (e.g. tendon sheaths)
- Indications: Extensor tendon repair
- Full tendon Laceration
- Partial tendon Laceration over 33% of tendon
- Contraindications for emergency department extensor tendon repair
- Neurovascular injury
- Thumb injury
- Zone 7 or 8 injury (distal wrist)
- Significant wound contamination or tissue destruction
- Closed Tendon Injury
- Associated Fractures
-
Laceration evaluation
- Extensive Wound Irrigation
- Evaluate for retained Skin Foreign Body
- Direct end to end repair of tendon
- Technique: Kessler Repair
- Wound Irrigation and exploration as above
- Extend fingers to best visualize tendon segments
- Consider proximal penrose drain or Blood Pressure cuff inflation
- May improve visualization if blood obscures surgical field
- Use braided non-Absorbable Suture (nylon) 4-0
- Proximal Tendon Segment
- Distal Tendon Segment
- Grasp distal tendon end in forceps
- Suture enters lateral (ulnar) tendon and exits on dorsal aspect of tendon
- Suture loops behind tendon ventrally from lateral to medial
- Suture enters medial (radial) tendon and exits on dorsal aspect tendon
- Tie the 2 Suture ends together
- Attempt to bury knot and cut the Suture ends close to the knot
- Perform Laceration Repair
- Disposition
- Splint wrist and finger in extension for 4 weeks
- Follow-up with hand surgery in 5-7 days
- Technique: Kessler Repair
- Alternative: Deferred Repair
- Wound Irrigation and Laceration Repair
- Splint wrist and fingers in extension
- Urgent referral to hand surgery for definitive tendon repair
VI. References
- Warrington, David and Deaton (2020) Crit Dec Emerg Med 34(12): 15