Bone Defects Caused by High-energy Injuries, Bone Loss, Infected Nonunions, and Nonunions

Bone defects represent a difficult problem for the clinician. They entail a sustained increase in hospitalization, risk of complications, and associated increase in expenses ( Fig. 1 ). The average cost for patients suffering from fractures following motor vehicle accidents has been estimated at US$10,000 per case. Nonunions cost about US$25,000; the estimate varies according to the location of the fracture site (humerus<tibia<femur). These direct costs apply only to nonunions that heal uneventfully after the first revision surgery. In contrast, bone loss imposes a longer period of treatment, and has an even higher complication rate and associated costs. To our knowledge, there is no published information on the costs incurred as a result of bone loss.

The term bone loss may refer either to structural defects and regions of missing bone caused by external factors or true defects and structural loss within existing bone, such as in osteopenia. Fig. 2 gives an overview of causes for bone loss.

By definition, primary and secondary bone loss can be differentiated. Primary bone loss may occur in bone diseases, such as malignancy. Secondary bone loss is most commonly caused by metastatic disease. Tumor metastases may have either osteoblastic or osteolytic features. Both damage the bone in terms of structure, nutrition, and metabolism. Trauma is the most common cause of bone defects ( Fig. 3 ).