Open and Closed Fractures

A fracture is called simple (closed) when the overlying skin is not broken and the bone is not exposed to the air; it is called compound (open) when the bone is exposed. When a bone weakened by disease breaks from a minor stress, it is termed a pathological fracture.

An incomplete, or greenstick, fracture occurs when the bone cracks and bends but does not completely break; when the bone does break into separate pieces, the condition is called a complete type. Fractured bones can also be classified by their configuration on the bone: a transverse fracture is perpendicular to the axis of the bone, while an oblique one crosses the bone axis at approximately a 45 degree angle. A spiral fractured bone, characterized by a helical break, commonly results from a twisting injury.

All fractures attempt to heal in the same fashion. The injured bone quickly produces new tissue that extends across the broken or cracked line and joins the broken pieces together. An impacted fracture occurs when the broken ends of the bone are jammed together by the force of the injury. A comminuted fracture is one in which the broken ends of the bone are shattered into many pieces. At first this new tissue is soft and puttylike; later, it is bony and hard. While re-forming, the bone must be protected from weight bearing and movement between the fracture ends.

The most common symptoms of fractured bones are pain and tenderness at the site, a sensation of grating or grinding with movement, and inability to use the limb or body part supported by the bone. Physical signs include deformity of the part, swelling in the region of the injured area, discoloration of the overlying skin, and abnormal mobility of the bone.

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.