Definition

Boutonnière deformity (BD) prevents straightening of the finger. The disorder affects the finger’s system of tendons. The tendons allow a person to flex and straighten his or her finger.

Tendons in Finger
Finger Tendon
Copyright © Nucleus Medical Media, Inc.

Causes

In BD, the tendon on the top of the finger (called the central slip) is torn or cut from the other tendons. This creates a tear that resembles a buttonhole (or boutonnière in French). The first finger joint is forced down and the fingertip bends back at the second joint. The tendons on this part of the finger are flat and thin. They are prone to injury. BD in the thumb affects a joint called the metacarpophalangeal (MCP).

BD can be caused by:

  • A powerful blow to the finger
  • A cut to the finger’s central slip
  • An injury to the first finger joint—called the proximal interphalangeal (PIP) joint
  • A severe burn on the hand

Risk Factors

Factors that may increase the risk of developing BD include:

Symptoms

Symptoms may include:

  • Pain and swelling on the top of the finger’s middle joint—the PIP joint
  • Inability to straighten the finger at the middle joint
  • Sign of injury (such as fracture or dislocation) to the PIP joint
  • Sign of injury (such as fracture or dislocation) to the MCP joint if the thumb is involved

Diagnosis

You will be asked about your symptoms and medical history. A physical exam will be done, paying close attention to:

  • Muscle strength
  • Joint damage
  • Range of motion
  • Presence of swelling
  • Evidence of infection
  • Tenderness in the finger

An x-ray may be done to see if you have a fracture.

Treatment

Treatment options include the following:

Medication

The following medications may be advised:

  • Corticosteroids—to reduce inflammation
  • Nonsteroidal anti-inflammatory drugs (NSAIDs)—to reduce pain and inflammation

Nonsurgical Approaches

For milder cases, the treatment is nonsurgical and may involve:

  • Splinting:
    • Applied to the middle joint to fully extend it
    • Used for 3-6 weeks
  • Stretching and strengthening exercises
  • Other techniques: massage, ultrasound therapy, electrical stimulation

If the finger does not improve, surgery may be needed.

Surgery

Surgery is needed in severe cases. For example, when the tendon is cut or when the deformity has lasted a long time. Surgery generally does not return the finger to the way it was working before the injury. But, there may be some improvement. After surgery, exercises can help to strengthen the finger.

Prevention

To help reduce your chance of getting BD:

  • Wear the proper equipment when playing sports.
  • If you have rheumatoid arthritis, ask you doctor about ways to protect your joints.

Revision Information