A mallet finger occurs when the extensor tendon to the distal joint of the finger is stretched or torn. The extensor tendon is on the top of the finger. The distal joint is the last joint near the tip of the finger.
The most common cause of a mallet finger is when the tip of a finger is forcibly jammed into flexion or hit against a solid object. It occurs often in sports such as baseball and basketball, when a ball hits the end of an extended finger. This injury causes the tendon on the back of the finger to be partially or completely torn; the tendon can no longer fully extend the distal joint.
A risk factor is something that increases your chances of getting a disease or condition. The primary risk factor for developing mallet finger is playing a sport or activity that exposes the finger to injury. For example, baseball and basketball.
Symptoms of mallet finger include:
- Pain and tenderness at the distal finger joint after injury
- Swelling and redness around the distal joint after the injury
- Inability to completely extend the finger
Your doctor may take an x-ray of the injured finger in order to look for a small fracture extending into the joint, which helps diagnose a mallet finger.
Treatment for mallet finger includes:
- Ice – for the first 1–2 days, ice should be applied for 15 minutes every 3 to 4 hours to reduce swelling and tenderness. Do not apply the ice directly to the skin.
- Pain medication – your doctor may recommend a prescription or an over-the-counter pain medication.
- Splint – a splint is usually applied to the outermost joint of the finger to keep it extended and prevent it from moving during healing. The splint should be worn for 4-6 weeks.
- Finger exercises – you may need physiotherapy after the splint is removed. These exercises will help improve strength, flexion, and extension of the injured finger.
- Surgery – in rare cases, surgery may be required. This may be the case if there is a total tear of the extensor tendon or if there is a fracture extending into the joint where the tendon has pulled a piece of bone loose.
With or without surgery, mallet fingers often result in some minor drooping of the distal finger joint. However, you should have close to normal function and be able to play sports.
The only way to prevent mallet finger is to avoid injury to your finger.