Anterograde Fixation Module for Posterior Acetabular Column Fracture: Computer-Assisted Determination of Optimal Entry Point, Angle, and Length for Screw Insertion

BACKGROUND: The aim of this study was to provide valid data for a plate-screw fixation model for fractured posterior-anterior columns of the acetabulum. MATERIAL/METHODS: Nineteen cadaveric bony hemi-pelvis specimens were obtained and 50 healthy adults were enrolled. The modified Stoppa approach and computed tomography (CT) imaging were used to collect the measured parameter data of the module. RESULTS: The measured parameter data were as follows: OP, 0.96±0.32 cm in females and 0.92±0.16 cm in males (P>0.05); PI, 0.98±0.28 cm in females, and 0.75±0.23 cm in males (P>0.05); ∠θ, 59.68°±6.28° in females and 56.75°±3.22° in males (P>0.05); and ∠ϕ, 41.27°±2.76° in females and 34.31°±2.78° in males (P<0.05). The corresponding CT image data were as follows: PI, 1.08±0.22 cm in females and 0.85±0.27 cm in males (P>0.05); OP, 1.06±0.29 cm in females and 1.12±0.24 cm in males (P>0.05); ∠θ, 55.33°±4.00° in females and 55. 50°±3.43° in males (P>0.05); and ∠ϕ was 39.21°±2.45°in females and 35.58°±2.31°in males (P<0.05). No significant difference with respect to sex and side existed between specimens and healthy adults (P>0.05). CONCLUSIONS: The measured parameter data obtained in healthy adults and cadaveric specimens provided an anatomic basis for the designation of the guide module, and thus confirmed the accuracy and safety of screw placement in fractured columns of the acetabulum.