Mallet Finger
A mallet deformity, or drop finger, is caused from a blow to the finger at the DIP joint that forces the joint into forced flexion. This injury typically occurs from playing call sports such as baseball, football, and volleyball. The patient will be unable to straighten the DIP due to an injury at the tendon insertion.
The finger is bent in hyperflexion and looks like a mallet due to the disruption of the terminal part of the extensor tendon from its insertion into the distal phalanx and the patient is unable to straighten the DIP. The patient will have a flexed finger and will be unable to do extension of the DIP. Mallet finger can occur as an avulsion fracture, bony, or purely a tendon injury. An x-ray may show an avulsion of the distal phalanx or subluxation of the joint.
Treatment
An extension splint of the DIP for about 6 weeks is the usual treatment. Movement should be allowed in the PIP joint. Night splinting may be needed for long periods.
Indications for surgery are: volar subluxation of the distal phalanx, avulsion fracture with a large joint fragment of more than 50%, and/or if it is an open injury. Mallet finger with subluxation of DIP joint is an indication for surgery. This may require an open or closed reduction and pinning of the fracture or the joint. A single pin is usually sufficient for the treatment of a purely tendon injury. Alternate method for pinning of a mallet with a fracture.
Complications of Mallet Finger include a residual deformity that usually does not affect the function or a Swan neck deformity. Care must be taken during treatment to avoid a Swan neck deformity and the PIP should be moving freely.
