Locating an iliac cortical window for reduction of an acetabular dome impaction: A computed tomography and cadaveric study.

This study aimed to determine the optimal location of the iliac cortical window (ICW) for the direct reduction of acetabular dome impactions using a reference bony landmark. Methods: In the first part of the study, computed tomography scans of 10 normal acetabula, the femoral head weight bearing area, were projected through the superior iliac cortical surface perpendicular to the plane of the true pelvis to show the area that corresponds to the acetabular dome. A line connecting each pair of anterior inferior iliac spines (AIIS) was drawn then reflected in the superior surface of the acetabulum and a reference point (RP) was marked on the line halfway between the AIIS and the pelvic brim. A 12-point 1-cm interval grid with horizontal and vertical axes labeled A, B, C and 1 to 4, respectively, overlying the acetabular surface projection was created to identify the location of the acetabular dome. In the second part of the study, the 12-point grid was marked on eight fresh cadavers (16 acetabula) and the same acetabular dome reference point was identified. K-wires were drilled into the acetabula using a parallel drill guide at each of the twelve grid points. An arthrotomy was carried out and the locations of the K-wires which penetrated the acetabular dome were recorded. Results: The average distance from the AIIS to the medial pelvic brim in the CT scans and cadaveric study were 47.7 and 45.9 mm, respectively. The K-wires at grid points B2 and C1 had a 100% correlation to the dome area. The A2, B1, and C2 grid points had a correlation with the dome area of >80%. The remaining grid points had joint penetrations ranging from 6.25% to 62.5%. Conclusion: The proposed RP, which can be easily identified intraoperatively, and the area 1 cm