107 patients with pelvic or acetabular fractures requiring internal fixation were randomized to receive prophylaxis against deep vein thrombosis with either a thigh-calf low-pressure sequential-compression device (Group A) or a calf-foot high-pressure pulsatile-compression pump (Group B). Patients were assessed for the development of deep vein thrombosis (by duplex ultrasonography and magnetic resonance venography), which trended toward lower prevalence in Group B, but did not reach significance. Higher rates of thrombosis were associated with increasing patient age and the time between injury and surgery.