Mallet Finger

Mallet finger is what happens when the small tendon that straightens the tip of your finger tears off the bone. With the tendon disconnected, the fingertip droops downward and you can't actively lift it back up — picture a tiny mallet hanging off the end of your finger. The classic mechanism: a ball or object strikes the very tip of an extended finger and forces it down. It's common in basketball, baseball, and football players.

Two flavors. A bony mallet means the tendon pulled off a small chip of bone with it. A soft-tissue mallet is a pure tendon tear with no bone involvement. The X-ray tells you which kind you have, and that influences how it's managed.

• Drooping fingertip. The tip of the finger hangs down and you cannot straighten it on your own — the hallmark sign.
• Pain and swelling at the last joint. Tenderness concentrates at the DIP joint (the joint closest to the nail).
• Immediate deformity after impact. A ball, mattress edge, or other object strikes the extended fingertip and forces it down — the droop appears right away.
• Passive extension is possible. You (or someone else) can gently push the fingertip straight, but it drops again as soon as it's released — because the tendon is disconnected.

The diagnosis is obvious by exam — the tip of the finger droops and you can't lift it on your own. X-rays are essential to see whether a chunk of bone came off with the tendon, and if so, how much of the joint surface is involved (more than about a third changes the treatment plan).

Surgery is rarely needed. Indications: a large bony fragment that's destabilizing the joint, or a failure of dedicated splinting to restore the tendon function.

External patient-education references and related OSI pages for additional background:

• Britannica — Hand (anatomy)
• AAOS OrthoInfo — patient education library
• OSI glossary — orthopedic terminology in plain language