To demonstrate the potential impact of computed tomography on orthopaedics, a brief review was done of four generations of scanners and of one new development (assay of bone mineral in the spine) that is presently being researched. To assess the utility of the method in treating orthopaedic problems, the cases of 140 patients, including patients with congenital anomalies, tumors, infections, and traumatic lesions, were analyzed. In the majority of the patients the technique provided useful information, often unobtainable with any other technique.