Boutonnière Deformity

An injury to the central tendon over the middle joint of the finger that makes it hard to straighten the joint.

A finger with the middle joint bent down and the fingertip hyperextended, the classic boutonnière position — The classic boutonnière position: the middle joint bends down, and the fingertip hyperextends upward.

What is a boutonnière deformity?

A boutonnière (buttonhole) deformity happens when the central part of the extensor tendon, called the central slip, is injured where it attaches over the middle joint of the finger. When the central slip is torn, the middle joint drops into a bent position and the fingertip snaps up into a straight or hyperextended position. The finger looks like it is being pushed through a buttonhole, which is where the name comes from.

Common symptoms

Swelling and pain over the back of the middle joint of the finger
The middle joint bends and cannot be fully straightened
The fingertip sits in a hyperextended position
Trouble straightening the finger to put on gloves or reach into a pocket
Tenderness on the top of the PIP joint (the middle knuckle)

Why does it happen?

Boutonnière deformities usually come from one of three causes:

A forced bend of the finger, such as when a ball hits the tip of a straight finger
A cut on the back of the finger that divides the central slip
Rheumatoid arthritis, which can stretch and weaken the central slip over time

If a fresh injury is missed, the deformity can become fixed over the next few weeks as the finger sits in the wrong position.

Side view diagram of a finger with boutonnière deformity and a torn extensor tendon over the middle joint — The central slip tears away from the middle finger bone. Without that attachment, the middle joint bends down.

Treatment options

Non-surgical treatment

Splinting. A splint is applied that holds the middle joint fully straight while allowing the tip joint to bend. The splint is usually worn full-time for about 6 weeks, then gradually weaned. Hand therapy guides this process.
Hand therapy exercises. Bending the tip joint while the middle joint is splinted helps the tendon heal in the right length and keeps the finger from getting stiff.

Surgical treatment

Direct repair. If the central slip is cut (for example, from a laceration), it is often sewn back together in the operating room.
Reconstruction. If the injury is old or the finger is locked in the boutonnière position, tendon reconstruction may be needed to restore balance to the finger.

What to expect at your visit

Dr. Barrera will examine the finger and test how well you can straighten the middle joint against gentle resistance. X-rays are often obtained to look for a small bone fragment. Early, closed boutonnière injuries usually do very well with splinting if treatment starts soon after the injury. Getting evaluated within the first week or two makes a real difference.

When to call the office sooner

Call us if you cannot fully straighten the middle joint of a finger after an injury, if the top of the middle knuckle is very swollen and tender, or if there is a cut on the back of the finger over the middle joint.

Questions?

Call your office location for non-urgent questions:

NYU Langone Laurelton · 646-501-4950
NYU Orthopedic, Woodside · 929-429-3222
NYU Orthopedic, Richmond Hill · 718-206-6923
Jamaica Hospital Ambulatory Care Center (ACC) · 718-301-0720

See our office contact information for addresses and fax numbers.