What is a Mallet Fracture (Finger)?

The phalanx bones (called phalanges in plural) are the long slender bones which form your fingers. There are three phalanges in each of the fingers, and only two phalanges in the thumb. Between each phalanx is a joint or finger “knuckle” that allow the fingers to move. Fractures are “breaks” or “cracks” in the bone, usually due to trauma. In severe injuries, multiple phalanges can be fractured. Mallet fractures are a common type of phalanx fracture that occurs due to jamming injuries at the end of the finger. A tendon attaches to the phalanx at the end of each finger, and when this part of the phalanx fractures, then end of the finger droops and won’t extend straight, because the tendon is no longer attached. Sometimes just the tendon ruptures producing the same effect without a fracture (mallet finger).

Mallet finger in the pointer finger of a person's hand

Causes

Most causes of mallet fracture involve trauma to the fingers:

  • Sudden “jamming” injuries to the fingers
  • Blunt force trauma (work injuries, sports, vehicle accidents)

Signs and Symptoms

Symptoms of a mallet fracture usually include one or more of the following:

  • Finger pain and tenderness to touch (usually mild at the base of the fingernail)
  • Finger swelling / stiffness
  • Finger bruising
  • Finger deformity (end of finger droops and won’t straighten)

Is there a Test for Mallet Fractures?

Yes! Often fractures are obvious on physical examination, but severe sprains and contusions can have a similar appearance. X-rays usually offer definitive diagnosis if a fracture is present and helps with treatment planning.

Treatment

Most mallet fractures can be treated nonoperatively, but occasionally surgery is required. It is important to start treating these as soon as possible, and to stick to the treatment recommendations very carefully as delayed care and noncompliance with splinting often result in poor outcomes including permanent drooping of the finger, nonunion (nonhealing of the fracture), and sometimes painful arthritis of the finger joint.

Nonoperative Treatment:
Splinting is the mainstay of treatment for most mallet fractures. A small splint is applied just to the end joint of the finger, allowing the other two joints to move. The end joint of the finger must be held straight at all times, as allowing it to bend even momentarily can reset the clock for healing or prevent healing altogether. We will show you techniques for cleaning and inspecting the skin of the finger under the splint without allowing the end joint to bend, then replacing the splint. We typically recommend six weeks of full-time splinting (removing only for hand hygiene), followed by 6 weeks of wearing the splint during high-risk manual activities and also at night-time. Occasionally, more than one round of nonoperative treatment is attempted if the deformity recurs.

Finger with a condition called mallet finger in an alumafoam splint. Finger splinted with a stax splint.
Stax Splint and Alumafoam Splint for Mallet Fracture



Operative Treatment:
Surgical repair is recommended for larger mallet fractures that allow the end joint of the finger to slip out of alignment. X-rays are useful to determine which mallet fractures need surgery. Mild sedation is administered, and the finger is numbed. Two or three small metal wires are placed through the skin and into the bone to hold the fracture pieces and joint in the proper alignment while it heals.  

Ready to confirm a diagnosis and fix the problem or just want to learn more?

Our board-certified orthopedic hand and wrist surgeons Eric Angermeier, MD and Kyle Kokko, MD, PhD, are here to help! They can often diagnose the problem in one visit, and get you started with a treatment plan. We offer a wide variety of both nonoperative and operative treatment options.

Call today for a clinic or telehealth appointment! 854-429-4263