UNC Health Talk

How a Broken Bone Heals

It’s a scene that’s not uncommon in sports: An athlete collapses to the ground with what seems to be a broken bone. Teammates and opponents kneel or stand quietly as the player is carried off to emergency treatment.

Something you can’t see on the field or court is what’s happening inside that player—and inside the body of everyone who breaks a bone. From the moment the bone fractures, the body is already at work repairing it. Amazingly, broken bones begin healing themselves immediately.

But that doesn’t mean the injured person won’t need the help of an orthopedic surgeon to get back on his or her feet.

Here’s how bones break and how they heal.

Symptoms of a Broken Bone

Bones can break in many ways. Sometimes bones crack, without breaking all the way through. When a bone breaks all the way, the two parts of the bone can stay in alignment, or the break might move apart. Bones can also shatter into three or more pieces. In some of the worst breaks, bones can pierce the skin, leaving the patient vulnerable to infection.

Broken bones typically cause swelling, pain, deformity and tenderness at the site of the break. Bruising and bleeding under the skin are common.

“Bones house cells that produce and make blood in our bodies. When you disrupt the architecture of the bone, it will bleed,” says Jeremy Miles, MD, UNC Health orthopedic surgeon.

Dr. Miles says people most often break bones in their shoulders, arms, wrists, hips and ankles. Hip fractures are more common in older people; those with osteoporosis are especially at risk.

If you’ve broken a bone, it’s important to make an appointment with an orthopedic surgeon soon after the break. This specialist can assess what type of fracture you have, offer the right treatment and track your healing process to make sure your bone is healing correctly. If a person with a fractured bone does not see a doctor, the bone could heal in an unusual position, which could cause a deformity or loss of function.

How Broken Bones Repair Themselves

If you’ve ever broken a bone, you know the pain typically comes quickly. Then, your nearby muscles tense as a protective mechanism.

“When a bone breaks, other muscles contract to decrease motion and try to stabilize the bone,” Dr. Miles says.

As this is happening, the body immediately springs into action to help heal the injury. The healing process is separated into three stages:

  1. Hematoma formation: Stem cells from bone marrow, blood and surrounding tissue travel to the fracture to trigger the formation of a hematoma, similar to a bruise under the skin.

“Fracture hematoma is an incredible substance,” Dr. Miles says. “It has molecules to stop the bleeding, as well as signaling molecules and growth factors to direct the body to heal the fracture.”

  1. Bone growth: The fracture hematoma or blood clot is gradually replaced by fibrous tissue, called soft callus. The soft callus becomes hard as it is replaced by bone. This new bony callus will fill the gaps between the broken ends of the bone, healing the fracture.
  2. Bone remodeling: Over the next several weeks, solid bone continues to grow and remodel at the fracture site. In general, it takes between six weeks and three months for a broken bone to heal, but it can take longer for complicated fractures.

“This is a continual process. Some bones will continue to remodel for over a year after a break,” Dr. Miles says.

Medical Treatment for Broken Bones

To stop broken bones from healing in the wrong shape, it is important that they are realigned into their original position. Sometimes, a doctor has to move the bone back into alignment, known as setting the bone or reducing the fracture.

Treatment can be surgical or nonsurgical, depending on the severity of the fracture and the patient’s age, medications and health conditions. Bones that have not been displaced or moved out of alignment can often heal with nonsurgical methods, Dr. Miles says.

To help with the healing process, the bones must be held in the correct position and protected as they heal. The most traditional way to do this is by using a brace, splint or cast. These can sometimes be used on the ankle, foot, knee, wrist, elbow or shoulder.

“It’s an external stabilizer,” Dr. Miles says. “If the internal architecture is disrupted, then we put support on the outside for a period of time to provide stability as the bone heals and regains its strength.”

In some cases, fractures may require surgery. The decision to perform surgery is based on the type of break, the type of bone broken and the force that is on that bone. Surgeries can involve the implantation of rods, plates, screws or pins after the bone is put back in place.

“In surgery, we help to augment or support the bone’s internal stability with an artificial device, usually made of metal,” Dr. Miles says.

“For an example, for a fracture of the thigh bone, we often put a metal rod inside the bone and attach it up near the hip joint and down near the knee joint. It provides stability inside the bone and new bone can grow around it while allowing people to walk on the broken bone as it heals.”

If a bone is broken around the hip or shoulder and is unlikely to heal, joint replacement is sometimes necessary. In joint replacement, the broken part of the bone and adjacent joint is replaced with an implant.

Preventing Bone Fractures

Whether you’ve never broken a bone or you’ve broken several, you can take steps to prevent future fractures:

  • Eat a healthy diet with adequate amounts of calcium and vitamin D.
  • If you’re a woman age 65 or older or a man age 70 or older, talk to your doctor about a bone scan for osteoporosis.
  • Limit alcohol.
  • Exercise to improve strength and balance.
  • Quit smoking. Smoking is bad for your bone health and impairs healing.

If you’re concerned about your bone health, talk to your doctor. If you don’t have a doctor, find one near you.