By: 25 October 2011

Philip To, MD, and Jeffry T. Watson, MD.
Boutonniere Deformity. In The Journal of Hand Surgery. January 2011. Vol. 36A. No. 1. Pp. 139-142.

Two hand surgeons from Vanderbilt Orthopaedic Institute in Nashville, Tennessee present a 30-year-old patient with a jammed and deformed index finger (boutonniere deformity). This affects the extensor tendon(s) of the finger so they no longer work properly. The injured area of the tendon is called the central slip. Damage occurs where the extensor tendon attaches to the middle phalanx (bone) of the finger.

Tightening of the tendon from injury or scarring can lead to a permanently crooked finger. The proximal interphalangeal (PIP or middle joint of the finger) gets stuck in a flexed (bent) position. At the same time, the distal interphalangeal (DIP) joint (moves the tip of the finger) is pulled up into too much extension (hyperextension).

The PIP joint may not straighten out completely under its own power. The finger can usually be straightened easily with help from the other hand. Eventually, the imbalance leads to the typical shape of the finger with a boutonniere deformity (tip of the finger extended too much, middle knuckle stuck in flexion).

So, back to the question about how to treat this problem? The surgeon has two choices. The first consideration is for conservative (nonoperative) care with splinting, range-of-motion exercises, and strengthening exercises. Many hand surgeons will try six weeks of splinting with the spring-type splint and exercise to see if the deformity lessens to a tolerable limit before considering surgery. This is desirable before surgery to stretch out a PIP contracture before repairing or reconstructing the extensor tendon.

Even with conservative care, surgery is required in some cases of boutonniere deformity. If it is just a matter of cosmetics (appearance), surgery may not help. If loss of motion has resulted in loss of function and disability, then surgery deserves a closer look.

Best results occur when the PIP joint is limber, rather than stuck in a bent position. If the PIP joint is stuck in a bent position, surgeons usually wait before doing surgery to see if splinting will help stretch and straighten the PIP joint. Splint immobilization may help restore full finger extension. In this position, the central slip may heal. But if it doesn’t, then here’s where the next dilemma presents itself: what type of surgery works best?

The surgeon can reattach the central slip and reconstruct the rest of the damaged soft tissue structures. Surgical procedures that can be used include lateral band reconstruction, central slip reattachment, central slip reconstruction, extensor tenotomy, or tendon and transverse retinacular reconstruction.

Each of these procedures has its own advantages, disadvantages, and indications (when to use each one). Some patients may need more than one operation. This concept is referred to as staged reconstruction. Decisions around what surgery to do and when to do it focus on how long ago the injury occurred, how much capsular (joint) stiffness is present, and the severity of the extensor lag (finger doesn’t straighten all the way) traing the joint.

# If the finger still won’t extend but the loss is less than 30-degrees, then the tendon can be cut.

# If the lag is more than 30-degrees, another surgery is needed to repair the central slip and restore normal tension.

Finally, patient should be warned that maximal efforts often lead to minimal results. In other words, despite all their hard work in hand therapy, loss of motion, stiffness, and the inability to use the finger normally are often long-term problems.

The authors conclude by saying this case report helps demonstrate the need for more research to define the best ways to treat the problem of boutonniere deformity. The goals of treatment should go beyond appearance and provide a means of restoring motion and function. At the present time, there are no studies comparing different procedures against conservative care or in comparison with each other. That’s the next step for future research in defining the most effective treatment for Boutonniere deformity.