The major characteristic of osteoporosis is low bone mass. The most clinically significant complication of osteoporosis is fracture. Three factors determine the likelihood of fractures:
Vertebral fractures occur with accelerated loss of cancellous bone. Vertebral compression fracture rates now appear to be equal in men and women but because women live longer than men, the lifetime risk of vertebral fracture is greater in women.
Typically, the vertebral fractures affect T8 - L3. The fractures often occur during regular daily activities, such as bending, lifting, or rising from a bed or chair. It is estimated that only 30% of vertebral fractures are symptomatic and are only detected upon radiographic examination. Most often, the patient will experience immediate severe, local back pain that subsides within several months. Altered spinal mechanics may result in chronic pain, loss of height, kyphosis, physical deconditioning due to inactivity, disability, and changes in self-image. Although rare, pulmonary dysfunction may occur due to thoracic shortening. Some patients may experience abdominal bloating, constipation, and early satiation due to thoracic shortening. With severe vertebral fractures and their attendant complications, men suffer adverse outcomes to the same, if not greater, extent as women.
Hip fracture is another important manifestation of osteoporosis, and often has the most severe complications. The population affected tends to be older; and therefore, the morbidity and mortality rates are increased. The most common acute complications include pain, depression, and mechanical failure of the surgical procedure. Approximately 20% of patients with hip fracture die within one year of the fracture, and more than 50% of the survivors are unable to return to independent living.
Long-term disability from distal radius fractures is uncommon. However, these fractures tend to promote fear of additional falls and fractures, fear of loss of independent living, and depression.