Tendons in your fingers connect the finger bones to finger muscles and help bend and straighten the finger at the joint when the muscles contract. Boutonnière deformity is a condition in which a tendon injury to the middle joint of the finger results in the inability to straighten the affected finger.

Boutonnière deformity can occur as a result of forceful trauma to the top of the middle joint when bent, laceration to the middle joint or from arthritis. Symptoms associated with this deformity may appear immediately or after a few weeks and may include swelling, pain and restricted movement. In severe cases, a fragment of the bone may be displaced from its original position.

The condition can be diagnosed by physical examination of the hand, and an X-ray may be recommended to confirm diagnosis.

Boutonnière deformity can be treated both surgically and non-surgically.

Non-surgical treatments include:

• Application of a splint to the middle joint of the affected finger to straighten it and allow the tendon to heal
• Exercises to improve the flexibility and strength of your fingers
• Protecting your finger by taping it or using protective splints
• Use of oral medications or corticosteroid injections

Surgery is performed when the injury is caused due to rheumatoid arthritis, the tendon is severed, presence of bone displacement, or if non-surgical treatments fail to provide relief. Surgical treatments improve the functioning of the finger but may not always correct the appearance depending on how soon surgery is initiated.