Anatomic Assessment of the Acetabular Fossa for Screw Fixation in Acetabular Fracture

Purpose: To obtain spatial information on the acetabular fossa concerning ‘transacetabular screw’ insertion through the acetabular fossa parallel to the quadrilateral surface for fixing an acetabular fracture. Materials and Methods: Each hemipelvis harvested from 25 adult fresh frozen cadavers was sectioned into eight segments. This resulted in seven measuring points located along the outer margin of the acetabular fossa. At these points, we measured and compared the vertical thicknesses of cartilage and bone from the quadrilateral surface. Results: The average thickness of the thinnest portion of the acetabular fossa floor was 3.9±1.9 ㎜. The entire thickness of the bone and cartilage measured vertically from the quadrilateral surface at the 7 points ranged from 12.7±2.1 ㎜ to 17.8±3.8 ㎜. The thinnest safe space of exposed threads of the ‘transacetabular screw’ inserted through the acetabular fossa was consistently just below the posterior conus of the lunate surface, measuring 4.8±1.6 mm (p Conclusion: We suggest that ‘transacetabular screws’ can be inserted safely if due consideration is paid to the spatial characteristics of on the acetabular fossa. Screw insertion into the postero-inferior portion of the acetbular fossa should be done carefully.