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Condition/Disorder Synonym

  • BD

  • Buttonhole deformity

ICD-9-CM Code

  • 736.21 Boutonnière deformity

ICD-10-CM Codes

  • M20.0 Deformity of finger(s); boutonniere and swan neck deformities

  • M20.02 Boutonnière deformity

  • M20.021 Boutonnière deformity of right finger(s)

  • M20.022 Boutonnière deformity of left finger(s)

  • M20.029 Boutonnière deformity of unspecified finger(s)

Preferred Practice Pattern

Key Features


  • Injury of the central slip tendon, usually severed.

  • Generally occurs from a forceful blow to a flexed finger that may cause volar dislocation of the proximal interphalangeal (PIP) joint.

  • Signs and symptoms may develop in acute to subacute phase of injury.

  • Flexion of the PIP joint and extension (hyperextension) of the distal interphalangeal (DIP) joint.

  • PIP joint moves anterior through the central slip defect causing volar migration of the lateral bands and increased tension causes DIP extension.2

Essentials of Diagnosis

  • Diagnosis is usually made by clinical examination or x-ray.

  • Assess finger ROM.

  • Boutonniere classification

    • - I: Mild extension lag, passively correctable

    • - II: Moderate extension lag, passively correctable

    • - III: Mild flexion contracture

    • - IV: Advanced flexion contracture

General Considerations

  • Symptoms can occur up to a few weeks after trauma.

  • Inflammation around the joint.

  • Can be associated with trauma (forceful blow or cut of the tendon).

  • Rheumatoid arthritis (RA).


  • Adults

    • - Hit or blow onto the finger, basketball3

    • - Associated with inflammatory conditions (i.e. rheumatoid arthritis)

    • - Associated with genetic conditions (i.e. Ehlers Danlos syndrome)

Clinical Findings

Signs and Symptoms

  • Inability to extend finger4

  • Inflammation around the joint

  • Joint redness and pain

  • Pain with grasping

  • Flexion of the PIP joint and extension of the DIP joint in the fingers occur at the metacarpophalangeal (MCP) joint in the thumb

Functional Implications

  • Pain with grasping, holding objects

  • Inability to fully extend the finger, loss of 15 to 20 degrees of extension

Possible Contributing Causes

  • Trauma5

  • Rheumatoid arthritis (RA), usually nontraumatic2

  • Central slip tendon injury

  • Joint arthritis/injury

  • Ehlers danlos syndrome

  • Nerve damage

  • Burns

  • Infection

  • Osteoarthritis

  • Dupuytren contracture5

Differential Diagnosis

  • Pseudo-boutonniere deformity

    • - PIP joint flexion contracture with restricted flexion of the DIP

  • Gout

  • Mallet finger

  • Fracture

Means of Confirmation or Diagnosis


  • X-ray

Findings and Interpretation

  • Bone spur, location, and size



  • Anti-inflammatory

  • Corticosteroid injection

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