The records were reviewed of 162 patients who had been admitted to the Hospital for Special Surgery since 1950 with compression fractures of the spine and demineralization. Fifty-seven of the patients were excluded from this study because the diagnosis was known at the time of admission, adequate trauma to cause fracture had occurred, or the diagnostic study or follow-up had been inadequate.

In the remaining 105 patients, osteoporosis was thought to be responsible for the vertebral collapse in fifty-five patients, malignant bone disease in twenty-five, hypercorticism with rheumatoid arthritis in nine, and osteomalacia in six patients. Other conditions were responsible for vertebral collapse in ten patients.

The chances of a patient having primary or metastatic malignant bone disease were markedly increased if fewer than three vertebrae were collapsed and the patient was less than fifty-five years of age. In the younger-age group especially, a variety of unusual conditions other than osteoporosis produced the demineralization. In order to make a final diagnosis, complete and, often, repeated studies are necessary. It is important to establish an exact diagnosis since some conditions that produce vertebral collapse respond to specific treatment.