What is a mallet finger?
A "mallet finger" is a common condition that can result from a seemingly minor injury (such as tucking in a bedsheet, or removing clothing) or a sporting injury.
After such an injury it becomes impossible for you actively straighten the fingertip - so when you try to straighten all your fingers the tip of one hangs down, as seen in the photo on the left.
This is because the insertion of the extensor tendon (which straightens the end joint of the finger) has been disrupted. Sometimes it is the tendon itself that ruptures, and sometimes the tendon is intact but the bone that it joins onto has broken (fractured). Either way, the effect is that the tendon can no longer do its job of straightening the finger.
How is it treated?
You need to have an X-ray performed before the type of treatment can be determined, to see if there is a fracture or not.
If there is no fracture then I recommend that you wear a splint for 8 weeks and then wean it under supervision. The splint is made of moulded plastic and constructed specifically for your finger by a hand therapist. Because your finger will initially be swollen the splint will need to be revised during the course of your treatment as the swelling settles, to ensure that the splint still fits snugly.
You must not take the splint off during the 8 weeks (except as directed by your therapist), as any bending of the joint will re-injure the tendon and set back the healing process. Your therapist will also be able to advise you on the best way to wean the splint when this is appropriate, and can give you gentle exercises to get the end of your finger moving.
If your bone is broken you may require an operation, depending on the size of the broken bone fragment. If a significant portion of your joint is affected then surgery is usually recommended to restore the position of the joint surfaces. The type of surgery performed varies. It is performed as day case surgery and usually wires and/or screws are inserted to keep the bones in position while the break heals. These wires are removed after 4-6 weeks, and a splint must be worn to hold the completely finger still during the 6 week healing process. It generally takes less time for a fractured bone to heal (6 weeks) than a tendon (8 weeks); the time is measured from when the finger is placed in an ideal position, not from the time of the initial injury.
What if I do nothing?
Treatment is recommended, as if you do nothing you will not regain the ability to fully straighten your fingertip. The subsequent imbalance in tendon forces can also lead to the other joint in the finger becoming affected. Treatment for mallet finger is most successful if it is started within 2 weeks of the original injury, especially if you have a fracture. The longer you take to seek medical treatment, the longer your rehabilitation period will be.
What can go wrong?
If the finger is not held in the right position during healing the affected tendon can heal longer than its original length, giving your fingertip a permanent droop. If you seek early treatment and follow your surgeon and therapist's instructions precisely this is unlikely.
If you have a significant fracture you are more likely to develop arthritis and stiffness in that finger joint in the future, compared to if you had never sustained an injury. However, the rates of arthritis following this injury are not high.
If you need surgery the additional potential risks include infection (of the skin, soft tissues or bone), nail growth disturbance, chronic tenderness, delayed wound healing and complex regional pain syndrome.