An injury to the tendon that straightens the tip of your finger or thumb is called a mallet finger (or “baseball finger”). If you have a mallet finger injury, your finger will:
- droop at the tip
- look bruised and swollen
- may hurt
You also won’t be able to straighten your finger.
In this type of injury, the tendon may become torn or detached from the finger bone. If a bone fragment is also detached, it’s called an avulsion fracture.
Mallet finger is commonly known as “baseball finger” because the injury often happens when playing baseball. Damage to the tendon occurs when a hard ball (that you’re trying to catch or field) hits your fingertip. Mallet finger is also called drop finger.
In sports, any direct hit to your extended fingers from a baseball (or football, basketball, or volleyball) can rupture the tendon that straightens the tip of your finger. This is known as the extensor tendon. Other direct impacts, even those of lesser force, can have the same effect.
An impact injury to the extensor tendon will prevent you from straightening your fingertip.
A tendon is like a rope made up of collagen (protein) fibers that attach your muscles to your bones. An impact injury to the finger may tear only the soft tissue of the tendon. Or it may pull the tendon away from the fingertip bone (distal phalange). Sometimes a fragment of bone will pull away with the tendon.
Although a hard blow to the tendon is the cause of most mallet finger injuries, sometimes a minor force can injure the tendon. Injuries caused by a low impact occur more often in older women, during activities such as putting on socks or making a bed.
Your finger may feel painful after the injury, and your finger tip will droop. You’ll still be able to use your hand. Pain is often associated with a bone fracture.
Other mallet finger symptoms are:
- inability to straighten your fingertip unless you use your other hand to hold it up
If your nail is also injured and is detached from the nail bed or has blood under it, it may be a sign of a cut or a bone fracture. Seek medical help as soon as possible, as there’s risk of infection.
Your doctor will be able to diagnose mallet finger by examining your dropped fingertip. They may order an X-ray and possibly an MRI or ultrasound to see the extent of the injury to your tendon and bone.
An X-ray will show the rupture of the tendon, any bone fracture, and whether the bone is out of alignment. The ultrasound and MRI are more sensitive in imaging bone fragments that may be involved.
To treat the pain and swelling of a mallet finger immediately:
- Apply ice.
- Elevate your hand so that your fingers are above your heart.
- Take nonsteroidal anti-inflammatory drugs (NSAIDs)
It’s a good idea to see a doctor as soon as you can. Mallet finger injuries are usually treated without surgery, unless the injury is chronic.
Even if you don’t have much pain and your hand still works, it’s best to get treatment as soon as possible. But even delayed treatment with splinting can be successful.
If a mallet finger is left untreated, your finger can become stiff. Or the finger may develop a swan neck deformity, where the joint bends the wrong way.
A mallet finger in children involves an additional concern. The injury may affect the cartilage in the finger that controls bone growth. If it’s not treated, the child’s finger may become stunted or not grow properly.
Splinting is the first-line treatment for a mallet finger. The goal is to keep the fingertip straight in the splint until the tendon heals.
Usually, your mallet finger will stay in a splint for at least six weeks. After that, you’ll wear the splint only at night for another two weeks. You may be advised to wear your splint for other high-risk activities, such as manual work or sports, during those two weeks.
A 2014 study recommends keeping the splint on at night for six additional weeks after the initial six weeks.
The most common type of splint used is a plastic stack type. Your doctor may refer you to a hand therapist to custom-make a splint for you.
There are many types of splints available. Some are glued to your fingernail. Some may be padded. None has proven to be superior to the others.
You wear the splint when bathing or showering. Afterwards, be careful to keep the finger straight on a flat surface while you take off the splint to wash and dry it because if you bend it, you can stretch out the tendon again and have to repeat the healing process.
Your doctor will likely see you a week after the splint is put on to assess how the finger is healing.
It’s important to fully comply with the splinting routine. If the joint involved (the distal interphalangeal) is allowed to flex during the six weeks, you’ll have to begin the splinting process again.
In some cases, when the splinting routine is difficult, the doctor may insert a temporary pin to hold your joint straight for the eight-week healing period.
Surgery is generally recommended for complex mallet finger injuries. These include injuries where:
- The joint is not properly aligned.
- The tendon requires a graft of tendon tissue from someplace else on your body.
Surgery may be open, where the skin is cut to expose the tendon, or done with a needle puncture (percutaneous). Hardware will be inserted to keep the fingertip straight until the tendon is healed. Hardware options include:
In some cases, a suture may be used to repair torn bone. The hardware is removed once the finger has healed.
There’s an ongoing debate about whether surgery is better than splinting in complex cases. Studies have not shown any significant difference in the outcome of conservative and surgical treatment.
At issue is that surgery often involves complications, such as infection, stiffness, or osteoarthritis. A decision for open surgery generally is made if the benefits of surgery for proper healing outweigh the potential risks.
Each individual is different. Discuss with your doctor and a specialist whether surgery is necessary for your finger to regain its function.
Your doctor or hand therapist may give you an exercise to keep the middle joint of your splinted finger from becoming stiff. To do this:
- Hold your hand to support the middle joint on either side.
- Bend that joint, keeping the splinted part of your finger straight.
- Do this 10 times, 4 to 5 times a day.
Once the splint comes off, your doctor or therapist may give you other exercises to help regain motion in the injured joint. One is called a blocking exercise:
- Use your other hand to hold down (block) the middle joint of the injured finger.
- Bend only the last joint down for a count of 10 and then straighten it for a count of 10.
- Do this 2 to 3 times a day, for 5 minutes. This is to help regain flexion and to strengthen the tendon.
Recovery time for mallet finger is usually eight weeks. It can be longer if you don’t keep to the splinting routine as directed.
Most people heal well. You may not gain full ability to straighten the end of your finger at first. Your finger may be red, swollen, and tender. But these problems usually resolve after three to four months.
Sometimes there may be a little bump on the top of the involved joint, but it’s not painful and doesn’t hinder the function of the finger.
Mallet finger is a common injury caused when an impact damages the tendon of a fingertip. Most injuries can be successfully treated without surgery.
If you injure a finger and can’t straighten your fingertip, it’s best to see a doctor as soon as possible for treatment.
It’s most important to comply with the splinting routine for the full amount of time your doctor recommends. Research is ongoing into the best kind of splinting and surgery to treat mallet finger.