Posterolateral clamp placement on the pelvic brim provides optimal reduction of transtectal acetabular fractures fixed through the anterior intrapelvic approach.

Purpose: To determine the optimal position of reduction clamps applied to reduce transtectal transverse acetabular fractures approached through the anterior intrapelvic route.

Methods: Transtectal transverse fractures were created in sawbone hemipelvis models. Fractures were reduced and held with a large pointed reduction clamp with one tine centered on the quadrilateral plate and the other placed in one of nine various positions on the pelvic brim accessible from the anterior intrapelvic (AIP) approach. Reduction was assessed by measuring maximum gapping and step-off at the joint surface.

Results: The posterolateral pelvic brim clamp position provided the most accurate reduction with the smallest articular fracture gap (mean 1.09 ± 1.05 mm) and step-off (mean 0.87 ± 1.35 mm). This clamp position, compared with the other positions as a whole, also yielded the highest proportion of perfect reductions (0 mm maximum displacement) for both step-off (83% vs 34%; RR 2.4, 95% CI 1.7-3.2) and gap (88% vs 49%; RR 1.8, 95% CI 1.4 to 2.2).

Conclusions: When clamping transtectal fractures through the AIP approach, positioning the clamp posterolaterally on the pelvic brim appears to provide the best reduction in this fracture model.