Impact of pubic cut position on pubic root displacement in periacetabular osteotomy : a 3D CT simulation study

Periacetabular osteotomy (PAO) has become widely recognized as the gold standard for the correction of acetabular pathomorphologies. However, the pubic cut has raised concerns due to complications such as delayed union and its association with anterior hip syndrome. The aim of this study was to examine the impact of the position of the pubic cut on the displacement of the pubic root during PAO surgery.

The study included thin-sliced CT scans of 58 hips with symptomatic hip dysplasia. Overall, 3D simulations of PAO were performed in triplicate, incorporating three variations of the pubic cut, specifically positioned 5, 10, or 15 mm medial to the iliopectineal eminence. Full displacement of the pubic osteotomy was noted by two independent investigators. Analysis of variance was used for comparison between means. Logistic regression was used to determine factors influencing displacement of the pubic root.

The incidence of complete pubic bone displacement increased with the medial position of the cut, with rates of 17.24% for a 5 mm cut, 36.21% for a 10 mm cut, and the highest at 82.76% for a 15 mm cut medial to the iliopectineal eminence (p < 0.001). The odds of complete displacement were reduced ten-fold with a lateral 5 mm pubic cut (odds ratio 0.1, 95% CI 0.04 to 0.20, p < 0.001).

The position of the pubic cut is the most significant determinant of pubic root displacement in PAO surgery. Loss of contact at the pubic osteotomy is likely associated with delayed union and postoperative anterior hip syndrome. Choosing a lateral pubic cut positioned 5 mm medial to the iliopectineal eminence is expected to result in a ten-fold reduction in the risk of complete pubic bone displacement. Appreciating the results of this study when performing the pubic cut may help mitigate the risk of post-PAO anterior hip syndrome.