Pelvic ring injuries due to high-energy forces are among the most serious involving the musculoskeletal system. Life-threatening hemorrhage, local and distant associated injuries, deformity, pain and diminished functional capacity are all potential problems for a patient with a disrupted pelvis. There is a clear correlation between total blood loss, incidence of associated injuries, final functional result and the type of pelvic ring injury. Between January 1987 and December 1990, 66 patients with an unstable lesion, type B or type C in Tie's classification, were treated in the University Hospital Gasthusiberg of the Katholieke Universiteit Leuven. In 42 cases, primary stabilization was achieved by means of an external fixator, of the type "Monofixateur". The overall mortality rate was less than 7%, and 53 patients could be seen for follow-up 6 months to 4 years after injury. Our findings confirm that compared to type B lesions there is a higher incidence of pain, permanent deformity and diminished functional capacity in type C lesions (P < 0.05). The external fixator used in the immediate post-injury period provides an effective splint that reduces bleeding from bone and veins but cannot maintain reduction in lesions with rotational and vertical instability. In these cases, a semi-elective internal fixation, after defining the exact pathoanatomy by means of a CT-scan, should be performed in selected centers.