Extensor Tendon Injury

What it is

Extensor tendons straighten the fingers and thumb and bend the wrist back. On the back of the hand and fingers they lie just under the skin, and in places they are very thin, so they can be injured by shallow cuts or even by jamming a finger.

Common types

• Mallet finger: the fingertip droops because the tendon has come off the last bone
• Boutonniere deformity: the middle joint of the finger is stuck bent after the central tendon tears or is cut. It may not appear until days or weeks after the injury.
• Hand and wrist injuries: cuts on the back of the hand can make it hard to straighten the knuckles or lift the thumb

Treatment

Splinting: many closed tendon tears, including most mallet fingers and early boutonniere injuries, heal when the joint is held straight in a splint full-time for about six to eight weeks.

Surgery: cut tendons are usually repaired surgically, and a temporary pin may hold the joint straight while it heals. Tendons cut over the back of the hand almost always need repair, which usually goes well.

A boutonniere deformity that has gone untreated for a long time is harder to correct, which is why early evaluation matters.

Recovery

Hand therapy is a common part of recovery. Custom splints protect the healing tendon while keeping the uninjured fingers moving, which helps prevent stiffness.