Hand

The tip of my finger won't straighten: tendinous mallet finger and skin-tendon fixation

Hee Seung Nam, MD, Orthopedic Surgeon · October 15, 2026

One person came in after pulling hard on a towel and hearing a 'snap' at the tip of the little finger; the end joint then dropped downward and would not straighten on its own. Because the tip of the finger bends like the head of a hammer, it is called mallet finger.

Did a piece of bone come off, or is only the tendon torn?

The tendon that straightens the end joint of the finger (the extensor tendon) attaches to the back of the bone of the end segment. If the end joint is suddenly bent forcefully, this tendon tears, or the piece of bone to which the tendon attaches comes off with it.

This patient had no detached bone fragment on X-ray, so I diagnosed a tendinous mallet finger in which only the tendon is torn. If left untreated, the end joint stiffens in the bent position, and over time it can lead to a swan-neck deformity in which the middle joint bends backward.

Most heal with a splint

For a fresh tendinous mallet finger, a splint that holds the end joint straight is the basic treatment. A review by a Korean hand surgery team describes continuing to wear the splint for at least 6 weeks so the end joint does not bend, then wearing it only at night for about 2 more weeks. If the end joint is bent even once during this period, the healing tendon can pull apart again, so it is important to support the finger and keep it straight even when taking the splint off.

Surgery is considered, though, for people whose job or life makes it hard to wear a splint for long, who have skin problems, whose finger droops again after splint treatment, or in whom the tendon has healed stretched out over time. A Cochrane systematic review comparing splinting and surgery concluded that there is not yet enough evidence to judge in which cases surgery is truly needed. So the decision is made by looking at each patient's degree of injury and life circumstances together. This patient chose surgery in view of these points.

What is skin-tenodermodesis?

The tendon at the end of the finger is very thin and flat, so if the tendon is stitched only to itself, its holding power is weak and it tears again easily. Skin-tenodermodesis is an operation that removes a section of the stretched tendon together with the skin above it to shorten its length, and encourages the tendon and skin to attach firmly to each other. It is simple and gives stable results, so it is used when splint treatment has failed or for old mallet fingers.

Figure. A simplified redrawing of the steps of the modified skin-tenodermodesis introduced by Professor Joon Goo Lee's research team.

The 6-week recovery

1. 2 weeks after surgery

   The skin had healed and the skin sutures were removed.

2. 4 weeks after surgery

   The sutures supporting the tendon and skin together were removed.

3. 6 weeks after surgery

   After confirming that the tendon had healed enough, I removed the wire that held the joint. For about 2 more weeks afterward he wears a splint at night that keeps the end joint straight, and from week 8 he moves it without restriction.

The end segment of the little finger, which before surgery drooped and could not be straightened on its own, regained a straight shape without flexion deformity and the ability to extend after 6 weeks.

In closing

• If the end of a finger suddenly droops and will not straighten, suspect mallet finger and check with an X-ray for a bone fragment.
• A tendinous mallet finger with only a torn tendon is mostly treated with a splint that holds the end joint straight for at least 6 weeks. The most important thing during this period is not to bend the end joint.
• When a splint is hard to use, has failed or the injury is old, skin-tenodermodesis is a simple and stable option.
• Do not dismiss it as “just slightly bent”; the earlier you are seen after the injury, the more likely a splint alone will be enough.

This article is general medical information. The treatment method can differ with the timing and degree of injury, your job and your lifestyle, so please confirm through an examination.