Dealing with patients who have a droopy finger can present diagnostic and treatment challenges for providers unfamiliar with this injury. A drooping finger is more commonly known as a Mallet finger injury. Mallet finger injuries occur when a forceful blow is delivered to the tip of a finger while the finger is flexed. Specifically, the extensor tendon is injured, resulting in the inability to actively extend the finger at the distal interphalangeal joint (DIP). This inability to extend the DIP gives the injured finger a droopy appearance.
Mallet finger injuries involve the Extensor Digitorium Profundus tendon as it inserts into the distal phalanx (DIP joint). This injury is classified as either a soft tissue injury (ruptured tendon) or a bony injury (avulsion fracture). In the soft tissue Mallet finger injury, the extensor tendon is ruptured at or near the tendon insertion into the distal phalanx. This type of injury shows no bony abnormalities on x-ray. In the bony Mallet finger injury, there is a portion on the distal phalanx that has avulsed or fractured off the distal phalanx. This bony abnormality will be readily apparent on x-ray. If the bony injury involves > 30% of the articular surface, then strong consideration should be given to surgically repair this bone fragment back to anatomic position. This will allow for restoration of function at the DIP joint.
Treatment of the soft tissue Mallet finger centers on placing the injured finger in an extended position to better approximate the ruptured tendon edges. In most cases, the tendon will heal and the DIP joint motion will be functional. Normal physiology of healing will allow the two ends to reapproximate. However, cosmetically, the involved DIP joint may have some drooping but will be able to actively extend the distal phalanx. As for the bony Mallet finger, again the objective is to reapproximate the bone fragments in order to allow them to heal. By extending the distal phalanx, the fragments should realign in reasonable anatomic position. If the bone fragment involves >30% of the articular surface of the distal phalanx, the extended position causes blanching of the skin, and/or the bone fragments do not reapproximate within 3mm of each other, these are cases where surgical repair is needed. Regardless of the type of Mallet finger injury, a stack splint or an aluminum finger splint will usually serve to adequately immobilize this injury. Again, in the case of a bony Mallet finger injury that does not reduce with extension maneuvers, neither the stack splint nor the aluminum splint will be effective.
Mallet finger injuries will usually take about 6-8 weeks for either a soft-tissue or bony Mallet finger injury to heal. An important point to reiterate with patients is to not try to flex the DIP joint during the healing process. Any disruption of the healing tissue will negate the healing time and the 6-8 week healing process will have to start all over. In these cases, the amount and quality of tissue healing will most often be less.
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