A fracture communicating with the external environment through a break in the skin or other viscus is described as an open or compound fracture. The wound is either produced from a sharp spike of the fractured bone (compounding from within) or through external penetration of an object. The risk of infection rises exponentially when a fracture is exposed to the external environment. Open fractures should therefore, be regarded as an orthopaedic emergency.

Mechanism of injury

The kinetic energy imparted to the tissues produces varying degrees of damage depending upon the amount of force applied. Severe forces may cause gross comminution of a fracture along with contusion, crushing or complete disruption of the surrounding muscles and other soft tissues.

Open fractures are usually caused by the following mechanisms:

Road traffic accidents: Direct impact on a body part causes shearing and disruption of tissues underlying the skin. A common example is an open tibial fracture sustained by a pedestrian after being hit on the shin by a fast moving vehicle.

Falls: Even simple falls may result in significant soft tissue disruption, and this is usually caused by the sharp end of the fractured bone.

Gunshot wounds: High or low velocity firearms cause tissue damage through two different mechanisms. The missile causes varying degrees of direct damage to the tissues, depending upon its distance from the body and also the amount of force imparted to it. The missile also produces destruction of the surrounding soft tissues through ‘shock waves’ generated around it.