Q & A: MALLET FINGER

by Lorenzo G. Walker, M.D.

Surgery of the Hand and Upper Extremity

QUESTION: Approximately three weeks ago, I jammed the tip of my ring finger against the shower door. It was painful for a few days, but the discomfort eventually diminished. What I have noticed is that I am no longer able to pull up the end of my finger and it seems to remain in a flexed position no matter how hard I try and extend it. A friend of mind suffered a similar injury when the tip of his finger was hit by a basketball and his finger has never completely gotten back to normal. Is this something I can ignore, or does this require medical treatment?

ANSWER: Mallet finger is the most common extensor tendon injury. The extensor tendons are located on the back of your hand and fingers and allow you to straighten your fingers and thumb. These tendons are attached to muscles in the forearm. As the tendons course into the fingers, they become flat and thin and are joined by smaller tendons from the muscles in the hand. It is the fine coordination of all of these small tendons that allow delicate finger movements and coordination. At times, a mallet finger occurs when the extensor tendon has been cut or merely separated from the bone. At other times, a piece of bone of variable size is pulled off with the tendon, but the result is the same: a fingertip that cannot be straightened. These injuries occur commonly with relatively

trivial trauma and are also quite prevalent during sporting activities. The vast majority of mallet finger injuries can be treated with splinting, although there are indications for surgical intervention. Although there are many ways to splint a mallet finger, Dr. Walker prefers to splint your finger into mild hyperextension with an Alumafoam splint, which should remain in place constantly for 6-8 weeks and cannot be removed. Instructions will be given to you in the office with regard to changing the splint and assistance is mandatory during splint changes, as it is very difficult to perform this maneuver by yourself. Removing the splint early will allow drooping of the fingertip, which then may obligate additional splinting or surgery. Dr. Walker will instruct you as to whether 6-8 weeks is the most appropriate period of splinting and may also suggest that you wear a splint at night for approximately four weeks after the initial splint is removed to prevent recurrent trauma to the finger, which may cause a recurrence of the same injury.

After your injury, an x-ray should be taken, as the size of any fragment associated with the injury and the displacement of the fracture fragments may indeed dictate your treatment course. The x-ray is also taken to ensure that the bones across your joint line up correctly. If they fail to line up exactly right, splinting will not be successful in eliminating the problem and surgery will be necessary. Surgery is also indicated in patients who are not able to keep their hand dry or wear a splint for the necessary time period. A fracture through the "growth plate" of a growing child is also an indication for surgery, as failure to reconstitute the joint surface could indeed result in alteration of growth. Surgery will likely also be recommended for patients whose injury is more than three months old, and for those who have sustained this injury as a result of a laceration. Another indication for surgery is a secondary deformity of the joint just before the end of the bone, which may droop as a result of tendon imbalance. Prevention of this tendon imbalance is one of the major reasons that treatment for mallet fingers is encouraged, as ignoring this injury could cause problems in the adjacent joints and even eventually affect other digits in the hand.

Regardless of whether the treatment is through splinting or surgical, one can anticipate that motion will be good but that there will be a very mild residual droop to the finger. A small prominence over the back of the joint may result and inflammation may take 3-6 months to eventually diminish.

Surgery consists of pinning of the joint to ensure straightness. The fracture fragments may or may not be pinned depending on its size and the time from injury. At that time, the tendon is repaired through a small incision to ensure that the two ends are in continuity and have an excellent chance of healing.

Therapy is rarely indicated initially, as the finger tends to regain its flexion rather quickly. Should this not occur over a 4-6 week period, you may be sent to a hand therapist for specific exercises to enhance flexibility of your finger at this point.

In neglected injuries where there is obvious cartilaginous loss to the digit, and in cases where the fracture fragment is not reducible, joint fusion may be required as a salvage procedure to eliminate pain and maximize function.