Why Do Bones Break?

The Three Distinct Reasons Why A Fracture Occurs

fracture bone
Broken bones can occur for a variety of reasons. Matt Meadows / Getty Images

Broken bones are common injuries. In fact, the average person will sustain two fractures over the course of their lifetime. Is there a difference between a fracture and a break? Despite the common perception that these words have different meanings, they, in fact, mean exactly the same thing. A fracture and a break are the same!

Fractures occur for one of three reasons:

  • High-Energy Injury
    In high-energy injuries, bone is broken because the force acting on it was significant. These injuries would include falls, car crashes and sports injuries. These types of injuries are often called "traumatic fractures."
  • Stress Injuries
    A stress fracture is due to repetitive microtrauma to the bone. Over time, the body cannot keep up with the forces acting on the bone, and a fracture eventually occurs. This is not a sudden injury, but gradually worsens over time.
  • Pathologic Injury
    In a pathologic fracture, the bone is abnormally weakened by some underlying problem. Causes of pathologic fractures include osteoporosis, tumors and infections.  Because the disease has weakened the bone, fractures can occur relatively easily.

Therefore, fractures occur either because of too much energy (all at once or over time) or insufficient bone strength.  The reason it is important to determine the cause of the fracture is that it can have important implications for both the treatment and the healing of the fracture.  That's why not all fractures are treated the same.  Even when two very similar fracture patterns occur, the characteristics of the patient and the cause of the fracture may lead to very different treatment recommendations.



Boden BP, Osbahr DC "High-Risk Stress Fractures: Evaluation and Treatment" J. Am. Acad. Ortho. Surg., November/December 2000; 8: 344 - 353.

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