Mallet FInger

A mallet finger occurs when the extensor tendon at the tip of a finger ruptures. The rupture of this tendon can involve the tendon alone, be associated with a small bone fragment or fracture or can be associated with a fracture that requires significant care.

The force applied to the finger can come from something as simple as tucking in a bed sheet or can come from a direct blow to the end of a finger. Mallet finger has also been known as baseball finger.

A mallet finger often begins with pain at the distal joint of the finger.  At times there is an immediate loss of motion while at other times the finger seems to stay straight for a while and only later starts to lose its ability to be extended actively at the tip.  These  injuries are typically "closed"  in that the skin and nail is intact but at times there is an injury to the skin or nail bed as well. The injury may seem "closed" but actually is "open" and can become infected at times.  In severe cases the injury is  clearly associated with an open injury to the joint or bone, a so called open or compound fracture. Sharp or penetrating injuries can cut the tendon and enter the joint as well but treatment of those sharp injuries may not follow the same treatment as a typical mallet finger does.

In adults the injury can involve the joint surface.  In children it can involves the growth plate or physis.

The diagnosis is often made based upon the type of injury and the appearance of the finger.  The fingertip will droop down and there is a loss of active motion.  Often the finger can be passively pushed up to straighten it but the independent active motion to extend the digit at the tip has been lost

X-rays are often taken to further delineate the injury and see how much if any bone, joint or growth plate is involved

Treatment depends largely upon the extent the soft tissue and underlying boney injury.

Tendon rupture without bone injury

Types of splints used to treat mallet finger. A, Dorsal aluminum splint. B, Commercial splint.

Most of these mallet finger injuries can be treated with splinting.  The splint can be applied in a variety of ways depending upon the injury.  Typically the split is left in place full time for six to eight weeks with a time for part time splinting after that depending upon what daily activity is done by the patient with a typical part time period of 4-6 weeks more.  In some situations pinning of the joint is used rather than a splint.

Tendon rupture with a small bone fragment

These injuries typically are treated like non-boney injuries

Tendon rupture with a large bone fragment involving the joint.

These injuries may respond to splinting and splinting is often used however a small bump may always be present a t the joint.  At times if the doctor feels that that the bone fragment is large enough and the joint may be unstable surgery may be offered.  During surgery pins or small screws may be used and the joint itself may be pinned to prevent motion during the healing process. In some instances when there is bone injury and surgery  is not needed the repair process the body goes through actually takes less time to heal than when there is a non-boney injury.

Above: X-rays showing fracture at the insertion of the extensor tendon. In the first image on the left the fragment is displaced.  This will heal with a bump but will be able to be treated with a splint.  IN the image on the right the joint has subluxated.  This subluxated joint can  need in certain instances to have a surgical repair.

In adults with severe open injury more immediate surgery may also be offered

Children

Mallet deformity from a fracture across the growth plate in a child is different than the adult fracture or tendon avulsion

In children  and adolescents the doctor needs to differentiate between these injuries that require reduction or realignment of the bone without surgery and those who may have a portion of the nail bed significantly torn or retained within the fracture site or growth plate.  Often children will not have a tendon injury but a fracture through the physis which appears to be a mallet injury.  X-rays often will reveal this. A special class of injuries known as Seymour fractures can occur in children with open growth plates and these MUST be differentiated from a simple mallet injury through the growth plate. Seymour  fracture injuries can be more complex and a hand surgeon who is familiar with pediatric fractures ( which the surgeons at the hand center are) should be consulted in any child' or adolescent mallet injury.  The typical age for persistent growth plates is age 15- 16 years in the fingers.

Late or Delayed Treatment in adults

Delayed treatment of mallet finger deformity may consist of splinting initially and at times surgical methods are offered to correct chronic deformities and other associated joint and tendon problems that may accompany the chronic situation

Results

Swan neck deformity from tendon imbalance and laxity at the proximal joint.

Most mallet fingers heal well, although often there is a slight loss of full extension. The slight extension loss typically has no effect on hand or finger function, but if left untreated it can cause other issues to occur in the finger due to tendon imbalance. While treatment of a closed mallet finger is not an acute emergency, the improper, partial or untreated injury can lead to further problems such as a swan neck deformity.

Note: Some material ( written and photos) taken from http://orthoinfo.aaos.org/topic.cfm?topic=a00018

Is activity possible with a Mallet Finger

Yes activity is permitted. Even encouraged as one needs to keep the other joints of the same finger and the other fongers moving.  Much depends upon who you are and what you do but most do normal activity when this problem is being treated. The exception may be a child or someone who work environment does not permit it. Sports can be played but risks of injury or the difficulty while playing a sport or doing certain activities productively may outweigh the need depending upon the circumstances.

Successful treatment of most mallet finger injuries depends upon splinting or casting of one type or another. Taking a short cut or stopping treatment inthe middle of the time frame can lead to a worse result. Many mallet fingers heal with some differerence in the final motion of the fingertip but have good function.

Treatment for a typical mallet finger

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