Fractures are caused by a complex number of forces that exceed the bone's ability to absorb them. Twisting, shearing, bending, compression and torsion all play a role in the development of a fracture. The type of force applied to a bone during trauma in many respects determines the fracture pattern of the bone. Bones are generally stronger when they are compressed compared to when the force pulls (tension) on the bone.

Fractures can be classified as closed or open. Open fractures occur part of the bone has penetrated through the skin. Large bone pieces sticking through the skin are obvious indicators of an open fracture; however, frequently the bone will penetrate through the skin and then retract, leaving a hole in the skin. Although an open fracture can be dramatic and emotional, the prognosis is often similar to that of a closed fracture where the bone fragments have not penetrated the skin.

If your pet develops a fracture that was the result of a low energy (mild) trauma (such as walking down stairs or running in the yard), your veterinarian will want to determine if a preexisting disease that weakened the bone is present. Examples of such conditions that weaken bone include bone tumors (cancer) or metabolic bone disease. A thorough clinical and radiographic exam is necessary to define preexisting disease.

Because multiple disorders may occur with trauma, a thorough clinical examination is necessary. Cats that have been hit by a car should have a chest X-ray (radiograph) taken to evaluate for concurrent chest trauma.

Some cats may have subtle joint injuries or spinal injuries with their more obvious long bone fracture. It is imperative to evaluate these patients fully.