Pathologic Fracture - Definition, Causes and Treatment

A patient with a pathologic fracture of the hip.. X-Ray Image © Jonathan Cluett, MD

A pathologic fracture occurs when a bone breaks in an area that is weakened by another disease process. Causes of weakened bone include osteoporosis, tumors, infection, and certain inherited bone disorders. There are dozens of diseases and conditions that can lead to a pathologic fracture.  The common aspect is the bone is abnormally weak as a result of the disease, and therefore more susceptible to fracture.

 

How They Occur

A pathologic fracture usually occurs with normal activities--patients may be doing very routine activities when their bone suddenly breaks. The reason the pathologic fracture occurs is that the underlying disease process weakens the bone to the point where the bone is unable to perform its normal supportive function.

For example, a bone cyst may grow to a significant size where the tumor effectively eats away a significant portion of normal bone. This area of bone is now much weaker, and prone to pathologic fracture. When a broken bone occurs through the weakened area it is called a pathologic fracture.

Treatment of Pathologic Fractures

Treatment of a pathologic fracture is highly dependent on the cause of the weakened bone.  Some causes of a pathologic fracture may weaken the bone, but not alter the healing properties of the bone.  On the other hand, some causes of a pathologic fracture may prevent normal healing of the bone.

  As a result, some pathologic fractures require the same treatment as a normal fracture, while others may require highly specialized care.

Any patient who experiences a fracture without an injury that would normally cause the bone the break should be suspected to have a pathologic fracture.  If it is determined that the bone has been weakened by some condition, appropriate treatment of that condition can be recommended.

 

Many tests can be performed to help determine the cause of a pathologic fracture.  Some of these include:

  • Laboratory tests (including blood count analysis and calcium levels)
  • Imaging tests (including bone scans and MRIs)
  • Bone biopsy

The final test is a bone biopsy.  This means that a sample of the bone is obtained, either at the time of fracture repair or before, to determine the cause of the bone abnormality.  Bone biopsies can be helpful especially when tumors or infection is suspected as a cause of the pathologic fracture.

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