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Attachment Rupture of the Long Extensor Tendon (Mallet Finger, Mallet Thumb)

The extensor tendon of the finger is attached to the terminal phalanx (distal end of the finger). Disruption of the extensor tendon at this insertion (mallet finger) is one of the most common tendon injuries in sports. It is especially common in ball-handling sports. The usual mechanism of injury is that of a forceful bending applied to an actively straightening joint, typically when a ball unexpectedly hits the fingertip and forces the finger to bend. A small bone fragment may sometimes be torn loose together with the tendon. The bone fragment will show up on X-rays.
Mallet thumb is much less common than mallet finger. It is diagnosed from the inability to actively straighten the tip of the thumb. Symptoms and treatment are identical for both conditions.


– Slight tenderness is found between the nail and the first joint (DIP) of the finger.
– The fingertip is slightly bent, and the first (distal) joint cannot be actively extended.


The doctor may:
– X-ray the finger to evaluate for fracture fragments or malalignment of the joint;
– treat with a splint to keep the first (distal) finger joint extended. The splint should keep the first joint completely straight while allowing free motion of the PIP joint. The splint should remain in place continuously for a minimum of 6 weeks;
– operate, if a large bone fragment has been torn away and there is malalignment of the joint.

Healing and complications

– Participation in sports is allowed during treatment of mallet finger as long as the finger is continuously splinted in extension.
– Splinting has been shown to be effective in injuries left untreated for 3 months after injury.
– Chronic mallet injuries, if left untreated, may progress to a flexion deformity at the DIP joint, and hyperextension deformity at the PIP joint (swan-neck lesion).
Avulsion of the flexor digitorum profundus tendon (jersey finger)

Avulsion of the flexor digitorum profundus tendon (the tendon that bends the tip of the finger) at its insertion on the distal phalanx is an injury often seen in athletes. The injury occurs most often during football or rugby, and usually results from grasping the jersey or shirt of an opposing player. As the player pulls away, the finger is forcibly straightened while the profundus flexor tendon continues to try to bend the finger. Although any digit may be involved in profundus avulsion, the ring finger is most commonly
affected. Profundus avulsion injuries frequently go undetected in the acute stages.

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