Mallet Finger (baseball 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 pentrating 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
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 6 – 4 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.
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
In children 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.
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
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 of 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.