Acetabular dysplasia predisposes to osteoarthritis with increased frequency in the presence of abnormal femoral anteversion

In an article published in The Bone & Joint Journal titled “The role of femoral neck anteversion in the development of osteoarthritis in dysplastic hips“, researchers examined the CT scans of 36 patients with unilateral osteoarthritis and bilateral hip dysplasia. They calculated correlation coefficients between various geometric measures in the hip and the presence of osteoarthritis. They noted a slightly higher average femoral neck anteversion angle (19 degrees compared to 12 degrees) in the arthritic hips, despite similar lateral center-edge angles (12.2 versus 13.3) and concluded that these findings suggest an increased femoral neck anteversion angle is an important component of the increased risk of osteoarthritis in hips with acetabular dysplasia. However, as their analysis was done retrospectively and osteoarthritis was already present, there was no information to aid in determining whether treatment of the prearthritic dysplastic hip should target femoral anteversion in addition to addressing acetabular coverage. In addition, their univariable correlation coefficients were similar for both anterior acetabular sector angle and femoral neck anteversion angle, implying that axial estimates of acetabular coverage should be considered in addition to the lateral center edge angle.  More research is required in this area.