Fracture and the Patient’s Age

Bone fracture occurs when the bone tissue is subjected to tensile, compressive, or sheer force in excess of its strength. Both the strength of the bone tissue and the nature of the forces acting on the bone change from infancy to old age, both normally and as a result of a disease. Fractured bone sometimes develops slowly rather than suddenly. Fatigue, or stress, and the incidence and type of fractured bones change with age.

Most fractured bones occur without skin injury. The skin wound in open fractures is caused either by severe direct trauma or by a sharp bone fragment that pierces the skin from within.

The bone tissue in young adults has high resistance to mechanical deformation. A fractured cortical bone in adults require tremendous forces, such as those encountered in motor accidents, and are therefore often associated with severe skin injuries and other lesions of soft tissue. Bones in children are springy and resilient, and the membrane enclosing the bones—the periosteum—is thick. Angular deformation of long bones in children therefore often results in incomplete, or “greenstick,” fractures. In the elderly the bone tissue becomes more brittle, especially the chancellors bone in vertebrae and in shoulder, wrist, hip, and knee joints.

The forces acting on the skeleton of a child normally are defined by body size and weight. Fractured bones in children are therefore rarely severely displaced or associated with severe soft tissue injury. In adults age 20 to 50, fractured bones are often caused by direct high-energy forces that have an explosive effect on bone and soft tissues and may cause severely displaced open fractures. In the elderly, the injury is usually caused by mild forces acting on brittle bone. Such fractured bones are rarely associated with soft tissue injury and often involve cancellers rather than the cortical bone.