Mallet Finger and Jersey Finger: When to Worry

Creator: Dr. Pedro Loredo
Published: 2026-04-27

By Dr. Pedro Loredo, MD Triple board-certified hand surgeon

Medically reviewed by Dr. Pedro Loredo, MD · Last reviewed: 2026-04-27

Mallet finger is an avulsion of the extensor tendon at the back of the fingertip. Jersey finger is an avulsion of the flexor digitorum profundus (FDP) tendon at the front of the fingertip. They sound similar. They look similar. They have very different urgency. Mallet finger can usually be treated with 6 to 8 weeks of continuous DIP extension splinting if seen early. Jersey finger almost always needs surgical repair within 7 to 10 days, and outcomes drop sharply with each additional week of delay. Both injuries are easy to dismiss as a jammed finger. Both can leave permanent deformity if missed.

The Tendon Anatomy at the Fingertip

Each finger has two tendons that move the distal interphalangeal (DIP) joint, the joint closest to the fingernail. The extensor tendon runs along the back of the finger and attaches to the back of the distal phalanx (the bone underneath the fingernail). It straightens the fingertip. The flexor digitorum profundus (FDP) tendon runs along the front of the finger and attaches to the front of the distal phalanx. It curls the fingertip down.

Either of these tendon attachments can be torn off the bone by a sudden forced motion in the wrong direction. When the extensor tendon is avulsed, the fingertip droops: this is mallet finger. When the FDP tendon is avulsed, the fingertip cannot bend: this is jersey finger.

The injuries are mirror images of each other. They have completely different mechanisms and completely different treatment urgency.

Mallet Finger: Mechanism and Diagnosis

Mallet finger is an extensor tendon avulsion at Zone I of the extensor system, the most distal zone. The classic mechanism is a ball or other object striking the tip of an extended finger and forcibly bending it. The extensor tendon either tears at its insertion or pulls off a small fragment of bone (a bony mallet finger).

The hallmark exam finding is an extension lag at the DIP joint. The patient cannot actively straighten the very tip of the finger, although it can be passively pushed straight. The fingertip rests in a slight flexion posture, like a hammer or mallet head, hence the name.

Pain is over the back of the distal phalanx, often with mild swelling and bruising. An X-ray is essential to identify a bony fragment, which influences treatment. Most mallet fingers are pure tendon avulsions without a bone fragment.

Mallet Finger: Treatment

Most mallet fingers are treated nonoperatively with continuous DIP extension splinting:

A custom thermoplastic stack splint or store-bought aluminum splint holds the DIP joint in full extension. The PIP joint is left free to move.
The splint must be worn 24 hours a day for 6 to 8 weeks. Any flexion of the DIP during this period restarts the healing clock from zero.
Skin care under the splint requires a careful technique: the splint is removed only with the finger pressed flat against a hard surface, the skin is cleaned, the splint is reapplied, and the finger never bends.
After the initial 6 to 8 weeks, a tapering schedule (night-only splinting for 2 to 4 more weeks) helps the tendon mature.
Hand therapy is often introduced after splinting to regain motion and strength.

Surgery is considered for:

Bony mallet finger with a large fragment (more than 30 to 50 percent of the joint surface)
Volar (palm-side) subluxation of the distal phalanx
Failed splinting (extension lag persists after a full splinting course)
Patients who cannot reliably maintain the splint (occupational reasons)

Surgical options include open reduction and pinning, extension block pinning (Ishiguro technique), or open repair of the tendon.

The most important determinant of outcome is the patient's ability to maintain continuous splinting. Patients who follow the protocol have excellent results. Patients who break protocol often end up with a residual extension lag or swan-neck deformity.

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A short post from Dr. Loredo on extensor tendon injury at the fingertip. View on Instagram.

Jersey Finger: Mechanism and Diagnosis

Jersey finger is an avulsion of the FDP tendon from the distal phalanx. The classic mechanism is grabbing a jersey, shirt, or rope while the fabric pulls away forcibly. The patient is gripping firmly when the load suddenly pulls the fingertip into forced extension. The FDP tendon, which is contracting hard, is overpowered and tears off the bone.

The ring finger is most commonly involved (about 75 percent of cases). The hallmark exam finding is the inability to actively flex the DIP joint. With the PIP joint held in extension by the examiner, the patient cannot bend the fingertip. The finger may rest in extension while the other fingers naturally curl in a relaxed position.

Pain is along the front (palm side) of the finger and may extend up into the palm if the tendon has retracted significantly. There is often swelling along the flexor sheath. An X-ray is essential to identify a bone fragment, which is graded by the Leddy and Packer classification.

Jersey Finger: Treatment and Why Time Matters

Jersey finger almost always requires surgical repair. The exception is a small bony avulsion that remains anatomically reduced near the distal phalanx (Leddy and Packer type 3), which can sometimes be treated with splinting if the fragment does not displace.

The challenge of jersey finger is tendon retraction. When the FDP tendon detaches, it can retract up the finger:

Type 1: tendon retracts to the palm. The vincula (small blood vessels feeding the tendon) tear, compromising blood supply. Surgical repair must occur within 7 to 10 days, ideally within 1 week, before the tendon necroses or scars.
Type 2: tendon retracts to the PIP joint and is held there by an intact vinculum. Repair within 3 to 6 weeks is feasible but earlier is better.
Type 3: tendon retracts only to the A4 pulley level, held by a bony fragment. Repair within several weeks is feasible.
Type 4: tendon retracts and the bony fragment fractures separately. Combined fracture and tendon repair is needed.
Type 5: tendon avulsion with associated distal phalanx fracture (closed) or open injury.

The most common scenario is a type 1 injury where time is critical. After 3 to 4 weeks, primary repair is often impossible, and the surgeon must choose between staged tendon grafting (a longer, more complex surgery with less predictable results) or DIP fusion. Outcomes drop sharply with delay.

This is why jersey finger demands a hand and upper extremity surgeon evaluation within days of injury. A finger that cannot bend at the tip after a hard pull is jersey finger until proven otherwise. It should not be treated as a simple sprain.

Why Both Are Easy to Miss

Both injuries can present with mild swelling, mild pain, and a finger that mostly looks normal at rest. Patients often describe the injury as a jammed finger and try to manage it themselves. The key exam difference between a sprain and either of these tendon injuries is active motion:

If you cannot actively straighten the very tip of the finger but it can be passively pushed straight, suspect mallet finger.
If you cannot actively bend the very tip of the finger but it can be passively curled, suspect jersey finger.

A finger that can do both motions, even if painful, is much less likely to be a tendon avulsion. A finger that cannot do either motion is much more likely to be one of these injuries and should be evaluated quickly.

What Happens Without Treatment

Untreated mallet finger leads to a permanent extension lag at the DIP joint. The tip stays slightly drooped and never fully straightens. Over time, the imbalance between the weak extensor and the still-strong flexor can pull the PIP joint into hyperextension while the DIP stays flexed: a swan-neck deformity. Late treatment options exist but are more invasive (delayed splinting, surgical reconstruction, DIP fusion) and produce less predictable results than early splinting.

Untreated jersey finger leads to permanent loss of active DIP flexion. The fingertip cannot grip. Over months, the FDP tendon retracts, scars, and may necrose. Late reconstruction with a tendon graft or DIP fusion may be needed, but salvage results are inferior to a primary repair done in the first week or two. The retracted tendon can also affect the ring finger function in ways that secondary surgery cannot fully restore.

When to Seek Care Today

See a hand and upper extremity surgeon within days, not weeks, if any of the following are present:

The fingertip droops and cannot be actively straightened.
The fingertip cannot be actively curled to make a tight fist.
There is significant pain, swelling, or bruising at the fingertip after a jammed-finger or pulled-finger injury.
There is an open wound at the fingertip after such an injury.
The mechanism was a forced bending of the fingertip in an unusual direction.

Mallet finger seen early is almost always managed with a splint. Jersey finger seen early is almost always repaired with one operation. Both seen late become much more difficult to fix.

Frequently Asked Questions

How do I know if I have mallet finger or jersey finger?

Mallet finger: the very tip of the finger droops down and you cannot actively straighten it, even though it can be passively pushed straight. The pain is over the back of the DIP joint. The injury is usually a jammed finger, often from a ball striking the fingertip. Jersey finger: the very tip of the finger cannot actively bend down, even though it can be passively curled. The pain is along the front (palm side) of the finger and may be felt up into the palm. The injury is classically from grabbing a jersey or other fabric that pulls forcibly while the patient grips it tightly.

Can I treat mallet finger at home with a splint?

A splint can be a definitive treatment for mallet finger, but the rules are strict. The DIP joint must be held in continuous extension for 6 to 8 weeks, with no flexion at all, including during dressing changes and skin care. Any flexion of the DIP joint during the splinting period restarts the healing clock. A custom thermoplastic stack splint or store-bought aluminum splint can work, but the discipline of constant wear is what determines success. Most patients who see a hand surgeon early have excellent outcomes with a splint alone. Patients who delay or break protocol often need surgery.

Why does jersey finger need surgery so quickly?

Jersey finger is an avulsion of the flexor digitorum profundus tendon from the distal phalanx. When the tendon detaches, it retracts up the finger toward the palm. The further it retracts, the harder it is to retrieve and repair. If retraction is significant (Leddy and Packer type 1 injury), the blood supply to the tendon may be compromised, and surgical repair becomes difficult or impossible after 7 to 10 days. Late presentations (more than 3 weeks) often require tendon reconstruction with a graft, a much longer and less reliable surgery, or staged surgery, or fusion if the result is unacceptable. Early diagnosis and surgery within 7 to 10 days produces the best functional outcome.

What happens if I leave a mallet finger untreated?

Untreated mallet finger leads to a permanent extension lag at the DIP joint. The fingertip stays slightly drooped and cannot fully straighten. Over time, the imbalance between the now-weak extensor and the still-strong flexor can cause a swan-neck deformity (hyperextension at the PIP joint with flexion at the DIP), which is functionally worse than the mallet alone. Late mallet finger can sometimes be treated with delayed splinting (longer than 6 to 8 weeks), with surgical repair if the DIP joint has not become arthritic, or with DIP fusion if there is significant arthritis. Early splinting prevents these later, more invasive treatments.