What does it feel like?
Many patients recall a definitive moment when they jammed their finger against a hard surface, followed by a visible droop in the terminal joint of the finger and an inability to completely straighten the finger at the tip. This is often accompanied with pain over the back of the finger, just short of the base of the fingernail’s cuticle, and bruising and swelling.
What is it?
It is an avulsion of the extensor tendon at its terminal insertion into your distal phalanx. This may or may not involve a fracture of the bone. The avulsed extensor tendon means, clinically, that you cannot extend your distal interphalangeal joint (the farthermost joint at the end of your finger, located just before your fingernail), because the tendon is no longer attached to the bone to effect movement.
What causes it?
Often, a direct blow to the tip of the finger, causing a sudden unanticipated flexion injury to the joint, pulling off the terminal extensor tendon from bone, or the terminal extensor tendon with a bit of bone off from the rest of the bone.
What are my treatment options?
Fortunately, the majority of mallet finger injuries can be treated non-operatively. Your general practitioner will obtain an Xray of your finger to ascertain whether there is a fracture of your bone. A hand therapist should be seen as soon as possible, so that your finger can be placed in a splint. It is important to keep that joint straight and still so that the tendon can heal back down to bone.
If there is an associated dislocation or if the joint is subluxed (not quite in the right position), occasionally surgery is required. If there is any uncertainty, please seek a referral to a hand surgeon as soon as possible.
As with any injury, the sooner this is treated, the better your outcome.