Extensor Issues

Question 1

Discuss sagittal band rupture mechanism, PE key finding, treatment

Answer 1

• Occurs w/ trauma to Ext Zone V
  
  • Trauma often will cause rupture of either the radial or ulnar sagittal band
  • Physical exam will show either radial or ulnar deviation of the digit (depending which band ruptured - ie. If radial sag band ruptured then get ulnar deviation of digit due to ext tendon subluxation seen in Fig 2) and will have inability to extend MCP actively from MP flexion position (b/c lateral bands fall volar…making them more of a flexion pull); however when passive MP extension is performed they will be able to maintain it (since the pull will bring lateral bands back dorsally)
  • Tx: Yoke splint 6-8 weeks (Fig 3 & 4)
    
    • Indications for surgical repair:
      
      • If ext. tendon does not centralize w/ passive extension
      • if high level athlete
      • if injury chronic ( > 3 weeks)

Question 2

Central slip injury: discuss injury mechanism, PE finding, treatment

Answer 2

• Occurs due to hyperflexion and blunt injuries
  
  • (+) Elson’s test
  • Think about this is volar PIP fracture dislocations that are not treated properly with extension splinting/poss surgery! Small dorsal frag has central slip attached to it.
  • Treatment: PIP extension splint for 4-6 weeks with DIP motion
  • Boutonierre Deformity:
    
    • Happens due to chronic untreated central slip injury -> get volar subluxation of laterall bands.

Question 3

Discuss treatment of non-boney and boney mallet fingers

Answer 3

• Acute mallet w/o fracture (Non-boney mallet) -
  
  • Treatment:
    
    • 24 hr DIP extension splinting for 6-8 weeks
      
      • After successful treatment patients may experience slight extensor lag w/o fxnal deficit
• Bony Mallet -
  
  • Treatment:
    
    • Reduction and extension splinting -> if does not stay reduced perfectly then perform reduction and pinning (these rarely require surgical fixation)