Boutonniere deformity

Background

  • Extensor Zone III Injury over the PIP joint.
  • Most commonly central tendon is injured, causing FDS to be unopposed, thus causing flexion of PIP
    • Disruption of central tendon causes lateral bands to be displaced volarly, causing them to act like flexors
  • FDP still intact
Boutonniere deformity.jpg

Clinical Features

  • History of trauma to digit and painful PIP.
  • Forced flexion of actively extended finger
  • Direct blow to PIP
  • Jamming
  • Laceration distal to PIP can injure central tendon
  • On exam, will see hyperflexion of PIP with hyperextension of DIP and MP joints.

Differential Diagnosis

Hand and finger injuries

Evaluation

  • Elson’s test: bend PIP 90 deg over edge of table, extend middle phalanx against resistance. Should have weak PIP extension and DIP goes rigid as lateral bands have to work.
    • Positive test indicated rupture of central tendon slip.

Management

  • XR to assess for avulsion fracture of middle phalanx
  • If open or with displaced avulsion fracture: operative repair
  • Closed: splint in extension (Both DIP and PIP) for up to 6 weeks, refer to hand surgeon. NO flexion of DP permitted for duration of splinting, including during cleaning. Repair extensor tendon if injured.

Disposition

  • Hand specialist follow up if closed injury
  • Immediate consult if deformity is caused by open injury

See Also

External Links

References