Mallet Finger Injuries

A mallet finger typically refers to an extensor tendon avulsion injury at the distal interphalangeal (DIP) joint. This can be the result of a direct, isolated rupture of the terminal extensor tendon or due to a distal phalangeal base fracture. In both cases, the result is an inability to actively extend the DIP joint, leading to a characteristic flexion deformity of the fingertip that is often described as resembling a mallet or hammer. This injury most commonly occurs due to sudden, forceful flexion of an extended DIP joint, eg, when a ball strikes the tip of an outstretched finger.