Flexor Tendon Injury

Introduction

  • Traumatic injury to the flexor tendon (1)
      • Classified by the Verdan's Flexor Zones (See below)
          • Described as the injury position when the fingers and thumb are extended and not the initial surface laceration.
  • Mechanism of injury
      • Commonly results from volar lacerations and subsequent neurovascular injury
      • Closed avulsions of the FDP usually occur during contact sports ("Rugby Jersey Finger")
  • Anatomy (may help with assessment)
      • There are several flexor tendons in the hand
          • Flexor digitorium profundus (FDP)
              • Location: inserts at the base of distal phalanx of digits 2-5
              • Action: flexor of the DIPJ, assists with PIP and MCP flexion
              • Innervation: anterior interosseous n. (index + long fingers) and ulnar n. (ring and short fingers)
          • Flexor digitorium superficialis (FDS)
              • Location: inserts at the bodies of middle phalanges of fingers
              • Action: PIPJ flexor, assists with MCP flexion
              • Innervation: median n.
          • Flexor pollicis longus (FPL)
              • Location: within carpal tunnel (most radial structure)
              • Action: thumb phalanx flexor, assists with wrist flexion
              • Innervation: anterior interosseous n. (median n. branch)
          • Flexor carpi radialis (FCR)
              • Location: inserts on base of second MCP. Closest flexor tendon to median n.
              • Action: wrist flexor
              • Innervation: median n.
          • Flexor carpi ulnaris (FCU)
              • Location: inserts on pisiform, hook of hamate and base of 5thMCP.
              • Action: wrist flexor
              • Innervation: ulnar n.

assessment (2)

  • The laceration may cut the tendon in flexion or extension making it not visible
  • Assess neurovascular status as well as passive and active joint flexion in isolation
  • Noting the Verdan Flexor zone is useful when describing injury over the phone/trauma meeting
  • XR Hand:
      • AP, lateral, oblique

management (3,4)

  • Remove jewellery and keep patient NBM
  • Check tetanus status
  • Pain relief and if open injury consider antibiotics (consult local antimicrobial guidelines)
  • Wounds requiring further exploration in theatre and/or tendon repair should be washed out with copious saline or tap water irrigation
  • Close the wound and dress appropriately (non-adherent dressing first e.g. atrauman).
  • Place in a splint in Edinburgh position
  • Elevate and discuss with a senior
  • Likely will need a tendon repair under anaesthesia (GA or wrist block).
      • Rehab will involve early motion to progress to full active flexion.

references

1. Chiu TW. Stone’s Plastic Surgery Facts: A Revision Guide, Fourth Edition. CRC Press; 2018. 2. Green DP, Wolfe SW. Green’s operative hand surgery. Elsevier/Churchill Livingstone; 2011. 3. Griffin M, Hindocha S, Jordan D, Saleh M, Khan W. An overview of the management of flexor tendon injuries. Open Orthop J. 2012;6:28–35. 4. The British Society of Surgery for the Hand. Hand Injury Triage App [Internet]. [cited 2020 Feb 2]. Available from: handinjurytriageapp.bssh.ac.uk
Image References:Header: Licensed with Adobe Stock 2019Verdan's Zones - Made by Viktorija Kaminskaite
This page has been reviewed by:
1) Mr. Martin Shapev - Plastic Surgery Registrar, RD&E (09/02/2020)