Which medical history is characteristic of Boutonniere deformity?

Updated: Jan 18, 2018
  • Author: Jay E Bowen, DO; Chief Editor: Craig C Young, MD  more...
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Boutonniere deformity

  • Disruption of the central slip of the extensor digitorum communis tendon over the PIP joint produces the classic boutonniere deformity. This can be caused by blunt trauma over the dorsal aspect of the finger, with a deep laceration over the PIP joint, or with forced flexion of the joint.

  • Avulsion of the central slip results in a flexion deformity of approximately 15-30° due to unopposed pull of the flexor digitorum superficialis tendon. As a result of loss of extensor tendon function, in addition to localized pain and swelling, the PIP joint cannot be actively extended. One can think of this as the PIP "buttonholing" through the central slip.

  • Prevention of a boutonniere deformity requires a high index of suspicion during the acute stage of the injury. A central slip injury should be suspected in patients who present with pain mainly over the dorsal aspect of the PIP joint.

  • Radiographic findings are rare for the small avulsion fracture at the dorsal base of the middle phalanx. The best indication of central slip damage is inability to extend the PIP joint fully against active resistance. A central slip disruption is present unless proven otherwise when full extension cannot be performed.

  • Immediately after injury, examination will reveal a diffusely swollen PIP joint held in mild flexion. Active extension may be possible with the lateral bands. The diagnosis is made by palpating all 4 quadrants of the joint. This is confirmed if there is pain and inability to extend the PIP joint against resistance. Tenderness dorsally indicates a central slip injury.

  • Boutonniere deformities are graded I through IV.

    • A grade I injury is correctable passively.

    • A grade II injury is the case in which there is a PIP joint flexion contracture of less than 30° that is not passively correctable.

    • Grade III boutonnieres demonstrate a PIP joint flexion contracture greater than 30° and loss of flexion of the distal joint.

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