What Is a Boutonnière Deformity?

A Boutonniere deformity is an injury to the tendons in your fingers that usually prevents the finger from fully straightening. Tendons that run along the side, top, and bottom of the finger work together to bend and straighten the fingers. The top of the tendon attaches to the middle bone of the finger and is called the central slip. When this tendon is injured, the finger cannot fully straighten.

A Boutonnière deformity can develop immediately following an injury or it can develop later. A patient will experience swelling and pain on top of the middle joint and middle bone in the finger.

Common Causes

A Boutonnière Deformity is usually caused by impact to a bent finger. A cut on top of the finger can sever the central slip from its attachment to the bone. The tear can look like a buttonhole. This condition can also happen without a specific injurious event in people who have rheumatoid arthritis.

Diagnosis

To receive a diagnosis, a qualified healthcare professional in musculoskeletal disorders will first take a medical history and conduct an examination of the fingers and hand. The physician will have the patient straighten the affected finger and x-rays may be recommended to determine if there are any broken bones attached to the central slip of tendons.

Treatment

Non-Surgical
To retain full range of motion in the finger, this injury must be treated early. Non-surgical treatment including splints, exercises, and protection is usually favored.

To straighten the bent finger a splint will be applied. The splint should be worn the recommended length of time. As it heals, the splint helps the tendon to heal back onto the bone. People that participate in sports or activities may be asked to wear protective splints or taping.

Stretching exercises may be recommended to improve strength and flexibility in the fingers after a period of splinting.

People that develop a Boutonnière Deformity due to arthritis may be treated with oral medications or corticosteroid injections as well as splinting.

Surgical
Surgery may be an option in certain instances, such as the deformity not improving with splinting. Surgery can reduce pain and improve function, but may not be able to correct the finger to make it look like it did prior to injury.