Postoperative excessive anterior acetabular coverage is associated with decrease in range of motion after periacetabular osteotomy.

Abstract

The aim of this study was to evaluate the relationship between acetabular 3-dimensional (3D) alignment reorientation and clinical range of motion (ROM) after periacetabular osteotomy (PAO). 50 patients (58 hips) with hip dysplasia participated in the study and underwent curved PAO. The pre- and postoperative 3D centre-edge (CE) angles and femoral anteversion were measured and compared with clinical outcomes, including postoperative ROM. The correlation between pre- and postoperative acetabular coverage and postoperative ROM was evaluated. Postoperative abduction and internal rotation ROM were significantly associated with postoperative lateral CE angles (abduction; p < 0.001, internal rotation; p = 0.028); flexion and internal rotation ROM was significantly associated with postoperative anterior CE angles (flexion; p < 0.001, internal rotation; p = 0.028). Femoral anteversion was negatively correlated with postoperative abduction (p = 0.017) and external rotation (p = 0.047) ROM. Postoperative anterior acetabular coverage may affect internal rotation ROM more than the lateral coverage. Therefore, the direction of acetabular reorientation should be carefully determined according to 3D alignment during PAO.