What is a Boutonnière Deformity?

Boutonnière deformity is when the finger or thumb is bent down at the middle joint and bent backwards at the end joint (see photo above). This deformity can happen for a couple of different reasons, including:

  1. A cut tendon on the back of the finger or thumb
  2. Tearing or weakening of the tendon from a disease such as rheumatoid arthritis

These two reasons are what can cause the middle joint to bend down. The backwards bending of the end joint is caused after the middle joint bends because there is more pull on the end joint of the finger.

If you’ve injured your tendon, your best option is to seek treatment immediately. If you do not treat an injured tendon, your deformity will become worse, and it could result in permanent stiffness in your finger. Sometimes, your joints may not start bending right away, rather, it will happen over time. As soon as you notice this change, seek treatment. The earlier you seek treatment, the easier your recovery may be. If you catch an injury early, your deformity may heal with just a splint. If you wait, you may need surgery to repair the tendon.

For those with rheumatoid arthritis, you may need treatment other than a splint. Contact a hand surgeon to discuss the best treatment options for you, both surgical and non-surgical. You can learn more about biceps tendons and muscles at www.HandCare.org.

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