What Is Mallet Finger and How Is It Treated?

By Brian Butzen MD

The Basics

Mallet finger is an injury to the tip of your finger that causes it to droop downward, making your finger look like a mallet. It happens when the extensor tendon at the distal interphalangeal (DIP) joint is damaged—either the tendon itself ruptures, or a small piece of bone gets pulled off where the tendon attaches (called an avulsion fracture).

The result? You can't actively straighten your fingertip on your own, leading to a characteristic droop.

How Does It Happen?

Any forced bending of the finger while it's held straight can cause this injury. The classic scenario is a finger held rigidly in extension when struck on the tip by a softball, volleyball, or basketball—which is why mallet finger is sometimes called "baseball finger."

But it doesn't always happen during sports. Other common causes include:

• Forcefully tucking in a bedspread

• Pushing off a sock with extended fingers

• Accidentally jamming your fingertip against something

• Getting your finger caught in a door

The most commonly affected fingers are the long middle finger, followed by the ring finger, little finger, and index finger. Involvement of the thumb is rare.

Why Treatment Matters

If you don't treat mallet finger, the droop may become permanent. Worse, the imbalance of forces on your finger can pull other joints out of alignment, leading to a secondary deformity called a swan neck deformity—where the middle joint hyperextends while the fingertip stays bent.

How Is Mallet Finger Diagnosed?

If you notice your fingertip drooping and you can't straighten it on your own, you likely have a mallet finger. However, getting an x-ray is recommended. X-rays help determine whether you have a "soft tissue mallet" (tendon injury only) or a "bony mallet" (with a fracture). If a fracture is present, imaging helps assess how much of the joint surface is involved and whether surgery may be needed.

A medical professional should confirm the diagnosis—either a physician or advanced practice provider (NP or PA)—to make sure you're treating the right injury with the right approach.

Treatment: Splinting Is the Standard

Most mallet finger injuries heal well with consistent splinting—no surgery needed. The key is keeping the DIP joint (the last joint of your finger) in full extension so the tendon or bone can heal properly.

How Long Do You Wear a Splint?

The splinting timeline depends on whether you have a soft tissue injury or a bony mallet (with a fracture):

Soft tissue mallet (tendon injury only): 10 weeks of continuous splinting, followed by 4 weeks of nighttime splinting.

Bony mallet (with fracture): A minimum of 6 weeks of continuous splinting, followed by 4 weeks of nighttime splinting.

Why Nighttime Splinting After the Initial Period?

Once you've completed the continuous splinting phase, your finger isn't fully healed yet—it's just healed enough to start moving during the day. Daytime activities put stress on the still-healing tissue. Nighttime splinting gives your tendon or bone a chance to rest and continue structural healing while you sleep, when those stresses are removed. Think of it as giving your finger recovery time after each day's work.

The Golden Rule: Keep It Straight

During the continuous splinting phase, the DIP joint cannot flex at all—not even for a moment. Any flexion during this period can disrupt early healing and may require restarting the entire splinting period from the beginning.

This is where patient education and compliance make all the difference. The splint must stay on continuously, even during showers and sleep.

What Type of Splint Works Best?

There are many splint options available—Stack splints, custom thermoplastic splints made by hand therapists, and foam-padded aluminum splints (like the Mallet Pro splint). The best splint is the one that:

Mallet Pro Mallet Finger Splint

• Keeps the DIP joint in full extension

• Is comfortable enough to wear continuously for weeks

• Allows the PIP joint (the middle knuckle) to move freely

• Is easy to manage during splint changes

Splint changes are necessary to keep the skin healthy, but they must be done correctly—keeping the fingertip supported in extension the entire time. This is where many people run into trouble, and why proper instructions matter as much as the splint itself.

When Is Surgery Needed?

Most mallet fingers don't need surgery. Surgical referral is typically considered when:

• The distal phalanx (fingertip bone) is displaced forward (volar subluxation)

• There's a large or displaced fracture fragment involving more than 30-40% of the joint surface

• The injury is open (skin is broken)

Your doctor will determine if surgery is appropriate based on your x-rays and examination.

What Are the Outcomes?

Most mallet finger injuries heal well with proper splinting. A slight residual extensor lag (inability to fully straighten the fingertip) of around 10 degrees is fairly common in patients after treatment, but this typically causes no functional problems.

Sometimes a small bump remains on the back of the finger at the DIP joint, but the finger still functions normally. The key to a good outcome is starting treatment promptly and staying compliant with splinting throughout the entire treatment period.

The Bottom Line

Mallet finger looks alarming, but with proper treatment—consistent splinting followed by nighttime splinting—most people recover well. The keys to success are:

1. Get diagnosed by a medical professional (with x-rays to check for fractures)

2. Start treatment promptly

3. Use the right splint that's comfortable and keeps the fingertip straight

4. Stay compliant—no cheating, not even for a moment during the continuous phase

5. Follow through with nighttime splinting after the continuous phase ends

For more information about mallet finger, see the ASSH Mallet Finger Info Page