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RESEARCH PRODUCT

Retrograde Transpubic Screw Fixation

subject

description

In the vast majority of fragility fractures of the pelvis, fractures of the posterior and anterior pelvic ring occur combined. Fractures of the pubic rami above and below the obturator foramen are much more frequent than fractures of the pubic bone and fractures at the anterior lip of the acetabulum. Retrograde transpubic screw fixation is a minimally invasive technique for stabilization of pubic rami fractures. The anterior column corridor is a straight corridor between the anterior cortex of the superior pubic ramus near to the pubic tubercle and the external cortex of the ilium above the acetabulum. The minimal canal diameter, measured in 160 Japanese, was on average 13.5 mm for men and 10.7 mm for women. The mean length of the corridor was 124.6 mm in men and 123.8 mm in women. The spatial orientation of the cylinder, measured on 82 Chinese, was 39.7°, 20.8° and 42.7° to the transverse, coronal and sagittal planes, respectively. In Europeans, the average length of the corridor was 127.2 mm, the narrowest diameter 14.6 mm. Consequentially, the insertion of a 7.3 mm screw should be possible in all patients. Biomechanical studies are controversial. One study demonstrated that fixation of the anterior pelvic ring with a retrograde transpubic 4.5 mm screw obtains the same stability as with conventional 3.5 mm plating. Another study found a lower stability for retrograde screw fixation than for plate fixation of pubic ramus fractures. Preoperative planning, intraoperative imaging and the different steps of the procedure are explained in detail. There are only a few literature data on complications and outcome. In a retrospective study on 68 retrograde transpubic screw fixations; there were no neurologic, vascular or urologic complications. There were 16% fixation failures, related to lateral compression type injuries and higher patient age. To prevent implant loosening, we recommend using the maximum length of the anterior column corridor with the tip of the screw perforating the lateral cortex of the ilium above the acetabulum.