The role of the subchondral layer in osteonecrosis of the femoral head: analysis based on HR-QCT in comparison to MRI findings:

BackgroundNon-traumatic avascular osteonecrosis of the femoral head (ONFH) is a severe disease causing destruction of the hip joint, often necessitating total hip arthroplasty (THA) even in young patients. Magnetic resonance imaging (MRI) is commonly used for diagnosis of ONFH, but provides limited insight into the subchondral bone microstructure.PurposeTo analyze routine MRI findings in comparison to high-resolution quantitative computed tomography (HR-QCT) with a special focus on the subchondral layer and to estimate the importance of differences determining the indication for THA.Material and MethodsTwelve patients with ONFH were included before THA. Preoperative MRI and HR-QCT of the retrieved femoral heads were aligned using a registration algorithm. Pathological findings and trabecular bone parameters in matched areas were analyzed by two readers. McNemar, marginal homogeneity test, and Pearson’s correlation coefficient were used for comparison.ResultsSubchondral delamination was found in nine cases...