Conventional radiography and CT examination of pelvic ring fractures. A comparative study of 90 patients.

In a retrospective study, we compared the interpretation of conventional X-ray films of the pelvis and the CT images for 90 patients who were treated in our department for a pelvic ring fracture and who had a CT examination between January 1987 and December 1990. The conventional X-ray films and CT scans were interpreted independently by a team of two surgeons and one radiologist. Following Dunn, Berry and Connally, we classified the CT images as very helpful, quite helpful or no help at all. Only 52 of 105 (49.5%) existing bony or ligament lesions of the pelvic ring were recognized in routine X-ray films; 11 of them resulted in a false diagnosis. In 14 cases important additional information about the associated-soft tissue lesions was acquired. In the same CT session, 30 additional CT examinations were performed. Using the Dunn, Berry and Connally classification, only 18 (or 20%) of all CT images were classified as "not helpful". Fifty-nine examinations (or 65.5%) were "quite helpful" and 13 (or 14.5%) were "extremely helpful." In our retrospective study we demonstrated that a complete evaluation of the pelvic ring is not possible with a series of pelvic overviews alone. Fractures of the sacral body and lateral part of the sacrum are overlooked especially often, but second-degree lesions of sacroiliac joint are also often not seen.