Anteroposterior Thickening of the Femoral Neck With Aging Decreases the “Offset” in Men

Background:The contour of the femoral head-neck junction has been shown to have an effect on femoroacetabular impingement (FAI), which can lead to early osteoarthritis of the hip. This study uses computed tomography (CT) to investigate changes in the femoral head, femoral neck, and joint space with aging.Hypothesis:The ratio of the diameter of the femoral head to the diameter of the femoral neck would decrease with increasing age, thus diminishing the “offset” of the femoral neck and being a possible mechanism for cam-type FAI and resultant osteoarthritis.Study Design:Cross-sectional study; Level of evidence, 3.Methods:There were 20 male and 20 female patients from each decade, aged 20 to 80 years, who received pelvic and abdominal CT scans. In the axial plane, the femoral head and neck were measured from anterior to posterior, and the joint space was measured anteromedially. The ratio of the diameter of the femoral head to the diameter of the femoral neck was calculated, and patients with radiographic si...