Fractures of the scapular body with displacement may heal with malunion, but even this may not interfere with movement of the affected shoulder. However, displaced fractures in the scapular processes or in the glenoid do interfere with movement in the affected shoulder if they are not realigned properly. Therefore, while most scapular fractures are managed without surgery, surgical reduction is required for fractures in the neck or glenoid; otherwise motion of the shoulder may be impaired. Epidemiology
Scapular fracture is present in about 1% of cases of blunt trauma and 3–5% of shoulder injuries. An estimated 0.4–1% of bone fractures are scapular fractures.The injury is associated with other injuries 80–90% of the time. Scapular fracture is associated with pulmonary contusion more than 50% of the time. Thus when the scapula is fractured, other injuries such as abdominal and chest trauma are automatically suspected. People with scapular fractures often also have injuries of the ribs, lung, and shoulder. Pneumothorax (an accumulation of air in the space outside the lung), clavicle fractures, and injuries to the blood vessels are among the most commonly associated injuries. The forces involved in scapular fracture can also cause tracheobronchial rupture, a tear in the airways. Fractures that occur in the scapular body are the type most likely to be accompanied by other injuries; other bony and soft tissue injuries accompany these fractures 80–95% of the time.
Since scapular fractures impair the motion of the shoulder, a person with a scapular fracture has a reduced ability to move the shoulder joint. Signs and symptoms may be masked by other injuries that accompany the scapular fracture. Causes
Usually, it takes a large amount of energy to fracture the scapula; the force may be indirect but is more often direct. The scapula is fractured as the result of significant blunt trauma, as occurs in vehicle collisions. About three quarters of cases are caused by high-speed car and motorcycle collisions. Falls and blows to the shoulder area can also cause the injury. Crushing injuries (as may occur in railroad or forestry accidents) and sports injuries (as may occur in horseback riding, mountain biking, bmxing or skiing) can also fracture the scapula. Scapular fracture can result from electrical shocks and from seizures: muscles pulling in different directions contract powerfully at the same time. In cardiopulmonary resuscitation, the chest is compressed significantly; scapular fracture may occur as a complication of this technique. Anatomy
The scapula has a body, neck, and spine; any of these may be fractured. The most commonly injured areas are the scapular body, spine, neck, and glenoid rim; the scapular body or neck is injured in about 80% of cases. Fractures that occur in the body may be vertical, horizontal, or comminuted (involving multiple fragments). Those that occur in the neck are usually parallel to the glenoid fossa.