[Misinterpretation of anterior pelvic ring fractures in the elderly].

Clinical outcome following pelvic ring fractures of AO/OTA type-A in the elderly is often unsatisfying because the posterior pelvic ring fracture is underdiagnosed and patients with type B fractures were conservatively treated like patients with type A fractures. This so-called "A-B" problem was systematically analyzed in our patients with pelvic ring fractures. 183 patients were treated with pelvic ring fractures. Primarily, the injuries were classified as follows: 81 type A, 38 type B, and 64 type C. The diagnosis was changed from type A to type B injury in seven patients. Parameters of investigation included fracture type, duration of symptoms, treatment, and outcome score according to the German Multicenter Study Group Pelvis. Persistent pain in the sacral area over an average of 2 (1-6) weeks was found in all patients. The CT scan revealed in all patients a transalar sacral impression fracture in the sense of an internal rotationally unstable injury of type AO/OTA B 2.1. The treatment consisted in a supra-acetabular external fixator for an average of 3 weeks. After 4 weeks the mean pelvis outcome score was 9 (7-10) points. In cases of persistent pain for more than 2 weeks after transpubic pelvic ring fractures in the elderly further investigation by CT scan should be recommended to exclude a concomitant sacral fracture, which then could be safely treated by a supra-acetabular external fixator.