Central Slip Avulsion and Pseudoboutonniere Deformities

Ovid: 5-Minute Sports Medicine Consult, The

Central Slip Avulsion and Pseudoboutonniere Deformities
Jeffrey Feden
Razib Khaund
  • Boutonniere deformity describes a characteristic flexion deformity of the proximal interphalangeal (PIP) joint and hyperextension deformity of the distal interphalangeal (DIP) joint; it results from disruption of the central slip at or near its insertion onto the dorsal aspect of the base of the middle phalanx.
  • Mechanism of injury is often forced flexion of an extended PIP joint or volar dislocation of the middle phalanx, causing avulsion of the central slip.
  • Deformity of the finger may develop several weeks after an untreated injury.
  • Pseudoboutonniere deformity results from hyperextension of the PIP joint; the volar plate is ruptured, whereas the central slip remains intact.
Unknown incidence but relatively uncommon
Risk Factors
Ball-handling sports
  • Boutonniere deformity:
    • Following avulsion of the central slip, the intact lateral bands slowly migrate in a volar direction as the central slip retracts.
    • The head of the proximal phalanx “buttonholes” through the injured extensor mechanism.
    • The lateral bands become flexors of the PIP joint and extenders of the DIP joint.
  • Pseudoboutonniere deformity: Contracture and fibrosis of the volar plate following injury leads to a flexion deformity of the PIP joint.
  • Always consider injury to the central slip when an athlete “jams” a finger or has a PIP joint dislocation reduced.
  • Knowledge of the mechanism of injury and/or direction of a PIP joint dislocation also may localize the injury and guide treatment.
    • Forced flexion of an extended PIP joint or volar dislocation of the middle phalanx may cause central slip injury.
    • Hyperextension of the PIP joint or dorsal dislocation of the middle phalanx may cause volar plate injury.
Physical Exam
  • Early: Swollen PIP joint with dorsal tenderness, weak active extension, full passive extension; classic deformity is rarely seen in the acute setting.
  • Late: Flexion deformity of the PIP joint with hyperextension of the DIP joint
  • Unlike a true boutonniere deformity, pseudoboutonniere deformity is characterized by a fixed flexion contracture of the PIP joint, inability to achieve passive extension, and mild or absent DIP joint hyperextension.
Diagnostic Tests & Interpretation
Plain radiographs (especially a true lateral view) to evaluate for fracture, dislocation, and volar plate injury
Differential Diagnosis
  • Fracture
  • PIP joint dislocation
  • Volar plate disruption
  • Collateral ligament tears
Ongoing Care
The athlete's sport and position will dictate his or her ability to participate with the injured finger immobilized.
1. Hong E. Hand injuries in sports medicine. Prim Care. 2005;32:91–103.
2. Peterson JJ, Bancroft LW. Injuries of the fingers and thumb in the athlete. Clin Sports Med. 2006;25:527–542, vii–viii.
3. Lee SJ, Montgomery K. Athletic hand injuries. Orthop Clin North Am. 2002;33:547–554.
4. Aronowitz ER, Leddy JP. Closed tendon injuries of the hand and wrist in athletes. Clin Sports Med. 1998;17:449–467.
5. Rettig AC. Athletic injuries of the wrist and hand: part II: overuse injuries of the wrist and traumatic injuries to the hand. Am J Sports Med. 2004;32:262–273.
Additional Reading
Coons MS, Green SM. Boutonniere deformity. Hand Clin. 1995;11:387–402.
Hogan CJ, Nunley JA. Posttraumatic proximal interphalangeal joint flexion contractures. J Am Acad Orthop Surg. 2006;14:524–533.
736.21 Boutonniere deformity

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