Multiple drillings of the acetabular fossa induce early joint remodeling after rotational acetabular osteotomy for hip dysplasia

Abstract

We previously observed medial and/or lateral expansion of the subchondral bone in the acetabulum 3 years postoperatively in two out of three cases in which rotational acetabular osteotomy (RAO) was performed. Then we performed multiple drillings at the acetabular fossa in order to induce expansion of the medial subchondral bone in the acetabulum. The purpose of this study is to evaluate the effect of multiple drillings on early joint remodeling after RAO. Twenty-one women (21 joints) who had undergone RAO with multiple drillings at acetabular fossa (group D) were included. As a control group, 12 women (14 joints) without drillings in RAO procedure were observed (group C). The center-edge angle (CE angle), acetabular roof obliquity (AC angle), head lateralization index (HLI), and the angle between medial and lateral edge of acetabular roof (LOM angle) were measured on the radiographs preoperatively, at 1 month, 2 years postoperatively, and at the last follow-up. As regards the mean CE angle, AC angle, and HLI, there was no significant difference between the two groups. The mean LOM angle at 2 years and the last follow-up demonstrated significant difference between the two groups. Biomechanical and anatomical changes after RAO cause increasing stress to the medial side of the acetabulum. Moreover, bone marrow-stimulating procedure at acetabular fossa might be beneficial to develop early joint remodeling affected by bone marrow derived cells such as mesenchymal stem cells.