A broken knuckle occurs when there is a break in the long bones of the palm, which doctors call the metacarpals. Five metacarpals are present in the palm, and a break in the "neck," or the topmost part of the bone, is common.

That being said, a broken knuckle can also affect the metacarpal head and the base of the proximal phalanx.

Some common causes of a broken knuckle include punching, sustaining a blow to the hand, and falling directly onto the hand.

This article aims to help a person determine whether or not their knuckle is broken. It also covers some signs that it is time for the person to see a doctor.

a man feeling his hand to see if he has a broken knuckle Share on Pinterest
A person with a broken knuckle may experience difficulty moving the fingers.

A very common type of knuckle break, or fracture, is called the "boxer's fracture." This type of fracture occurs when a person punches something and breaks the top of the fifth metacarpal bone. This is the bone right below the pinkie finger.

When a person has this type of fracture, their knuckle will appear sunken compared with the other knuckle bones.

However, although the boxer's fracture is one of the most common knuckle fractures, a person can break any knuckle.

According to one article, the fifth metacarpal is the knuckle that people most commonly break. Fractures in the second metacarpal, below the index finger, are less common.

In people aged 18–34 years, metacarpal and finger fractures are the most common type of fracture in the upper extremities of the body.

Some symptoms of a broken knuckle include:

  • bruising
  • difficulty moving the finger on the injured knuckle
  • hand and finger swelling
  • numbness in the fingers and hand
  • pain
  • a visibly misshapen hand

The most common cause of a broken knuckle is punching or striking an object with the hand balled in a fist.

A doctor will begin diagnosing a broken knuckle by carrying out a physical examination and taking a medical history.

Sometimes, the hand's deformity or swelling is so significant that a doctor will easily be able to diagnose a broken knuckle.

A doctor will likely take an X-ray, which can help them identify areas where the bones may have broken. Sometimes, X-rays can help a doctor tell the difference between a sprained and a broken knuckle.

They can usually use a physical examination combined with imaging to diagnose a broken knuckle.

The more severe the symptoms, the more likely it is that the knuckle is broken. If the injury does not dramatically affect the knuckle's movement or cause much pain, it may just be a bruised knuckle.

The treatment options for a broken knuckle depend on several factors:

  • whether it is an open fracture (when there is a break in the skin) or a closed fracture
  • the number of affected knuckles and whether or not there are other nearby broken bones in the fingers
  • the severity of the break and how much it affects the knuckle and fingers

Sometimes, a doctor will "reduce" the fracture, or put the knuckle back into place. When this is the case, they may place a special cast around the thumb or hand to stabilize the fracture and allow it to heal without surgery. If this is not possible, they may use a splint or a brace.

A doctor may recommend that the person comes back to their office 1–2 weeks later to X-ray the hand again to ensure that it is healing properly.

However, if the break is very severe, the doctor may recommend surgery to allow the metacarpal to heal and reduce the likelihood that the person will have a permanent hand deformity.

There are several different approaches a doctor can take, including inserting wires or plates to stabilize the joint.

A doctor should discuss the extent of the injury and the person's treatment options. They should also discuss any potential side effects of treatment and what might happen if a person does not receive treatment for their injury.

When a person first breaks their knuckle, they can use the RICE method to treat any pain and swelling:

  • R is for rest. Resting the affected area can help it heal.
  • I is for ice. Applying cloth-covered ice packs for 10–15 minutes at a time can reduce swelling and help minimize pain.
  • C is for compression. Wrapping the affected hand in a soft cloth bandage can help reduce swelling and stabilize the injury.
  • E is for elevation. Elevating the extremity can reduce swelling and discomfort.

Once a doctor has cleared a person to start moving the affected knuckle, they may recommend physical therapy or some exercises to do at home. Examples might include squeezing a rubber ball and placing a rubber band around the fingers and stretching out the hand.

A doctor should discuss any potential complications from a broken knuckle if the person has had surgery to repair it. These complications include:

  • poor wound healing
  • stiffness
  • surgical site infection

In most cases, if a person has a splint, a doctor will instruct them to stop wearing it after 4–6 weeks. However, a person may receive individual instructions based on the nature of their injury.

A person should seek immediate medical attention if they have the following symptoms:

  • numbness in the fingers and hand, which could indicate nerve damage
  • severe pain
  • a visibly misshapen hand
  • swelling that seems to worsen and makes the fingers hard to move

These are all symptoms of a broken knuckle that may require surgical repair.

If a person thinks they have a bruised or sprained knuckle and their symptoms worsen over time, they should seek medical attention

Broken knuckles are a common yet painful occurrence. Treatments will depend on how severe the break is and the number of knuckles it affects.

If a person experiences a loss of sensation in their hand or has problems moving their fingers and thinks they may have broken their knuckle, they should seek immediate medical attention.