How Do Broken Bones Heal?

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It’s a rare individual who passes an entire lifetime without breaking a bone. Accidents happen. In the United States, several million of them result in broken bones (“fractures”) every year. It’s estimated that the average citizen will experience at least two fractures during their lifetime, not including broken teeth.

Compund vs. Closed Fractures
Open vs. Closed Fractures


Fractures are categorized in a number of different ways:

1)           A fracture may be partial or complete. A complete fracture means the bone is in two or more pieces and is what most people envision where they think of a broken bone. The break may, however, only go partially through the bone in question.

2)           A fracture may be displaced or non-displaced. If non-displaced, the two broken ends are relatively aligned. If displaced, the fracture may cause a limb to be positioned unnaturally (sometimes very unnaturally)

3)           A fracture may be open or closed. An open (compound) fracture is one in which the skin has been breached; the bone may protrude through the wound or may have retreated back inside. A closed fracture doesn’t have an open wound associated with it and is less likely to be infected.

Within the above, there are different types of fractures; some may conceivably fit in all three categories. They include:

  • Transverse fractures: breaks straight across the bone
  • Oblique fractures: breaks occur at an angle across the bone
  • Spiral fracture: breaks occurring in a spiral pattern, usually due to rotational trauma
  • Greenstick fractures: breaks on one side, but bends on the other–like breaking a “green” branch from a tree
  • Comminuted fractures: breaks into three or more pieces; a “shattered” bone
  • Compression fractures: collapse of bone structure, usually in the spine
  • Stress fractures: usually appear as very thin cracks; also called “hairline” fractures
  • Avulsion fractures: when a tendon or ligament pulls off a piece of bone.

Probably the most common symptom of a broken bone is pain. Immediately afterward, you might feel faint or even black out. At the point of injury, you can expect bruising, stiffness, and swelling, usually more than you’d see with a sprain. If the fracture is in an extremity, you may have difficulty using it. Oftentimes, the area will be markedly “out of place” from the normal position.


Okay, so you’ve broken a bone. What happens next? There’s a process, almost miraculous, that goes into healing a fracture. It occurs almost immediately and continues for years. The time it takes for a bone to heal depends on various factors, including age, location of the injury, and the type of fracture incurred.

Bone healing
Hematoma Formation

In the first few hours, a blood clot (called a “hematoma”) forms around the fracture. The hematoma contains proteins that help provide a “plug” which attempts to fill the gap between broken ends.

The body’s immune system then sends out cells called “phagocytes”. These entities are like a cleanup crew. They work to eliminate tiny bone fragments, debris, and bacteria in the area. Your circulatory system begins to form new blood vessels to provide circulation to the healing fracture.

Soft Callus
“Soft” callus formation

After a week or two, other cells known as “chondroblasts” form connective tissue known as collagen around the fracture. This is identified as a “soft callus”. It is stronger than the original hematoma, but not nearly as strong as bone.

“Hard” Callus Replaces “Soft” Callus

Cells called “osteoblasts” then begin to create actual bone by adding minerals to the fracture site. This is known as the “hard callus” and replaces the soft callus. This process usually takes 6-12 weeks to complete, depending on the type and location of the break. The end product appears like a thick bump on the bone.

Over time, bone cells called “osteoclasts” remodel the bone so that it ends up looking like the original structure. Osteoclasts accomplish this by removing excess bone that formed during healing. Remodeling may occur for years; in many cases, the final result looks so normal (after several years) that even X-rays may have difficulty revealing the fracture site.

Next time, we’ll discuss how to recognize the differences between a sprain and a fracture as well as how to treat fractures in off-grid settings.

Joe Alton MD

Dr. Alton

Find out more about fractures and 150 other medical topics in the award-winning Third Edition of “the Survival Medicine Handbook: The Essential Guide for When Medical Help is Not on the Way“. Also, learn a whole lot about bacterial infectious diseases and the antibiotics that treat them in “Alton’s Antibiotics and Infectious Disease: The Layman’s Guide to Available Antibacterials in Austere Settings. Lastly, fill those holes in your medical supplies by checking out Nurse Amy’s entire line at

Hey, don’t forget to check out our entire line of quality medical kits and individual supplies at Also, our Book Excellence Award-winning 700-page SURVIVAL MEDICINE HANDBOOK: THE ESSENTIAL GUIDE FOR WHEN HELP IS NOT ON THE WAY is now available in black and white on Amazon and in color and color spiral-bound versions at

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