A fracture is a break in the continuity of the cortex of the bone. It represents failure of the bone to respond to a high impact, which can be direct or indirect. Associated injuries to the adjacent soft tissues (e.g. ligaments, tendons, etc.) are not uncommon.

Mechanism of injury

Although most fractures occur due to direct or indirect trauma, other mechanisms may be responsible in some special situations.

Direct injuries

In these injuries, the forces are concentrated at one site and, therefore, the bone fails at the point of impact. Fractures occurring due to direct mechanisms are often comminuted and may be associated with significant soft tissue injuries. A typical example is a comminuted tibial fracture sustained by a pedestrian due to direct impact from a speeding car.

Indirect mechanisms

The force causing the fracture is applied at a distance in indirect mechanisms and therefore, associated damage to soft tissues may not be much. An intracapsular fracture of the femoral neck is a typical example of an injury with indirect mechanism. An olecranon fracture caused due to a sudden contraction of the triceps during a fall is another example of an injury from indirect forces.

Pathological fractures

Such fractures occur with trivial trauma to the bones that are already weakened by a disease process such as malignancy or infection. Pathological fractures occurring due to secondary malignant deposits in the hip often involve the subtrochanteric region. The patient may give a history of local pain or discomfort prior to fracture.