CT Measurement of Proximal Femoral Medullary Cavity Morphology in Healthy Subjects from Northern China

Abstract Purpose: In total hip arthroplasty (THA), optimal stability and fixation is achieved via tight adaptation of the prosthesis to the bone. This study aimed to analyze the proximal femoral medullary cavity morphology of Chinese subjects on three-dimensional reconstructed imagery to explore the factors influencing these parameters.Methods: CT was performed on 63 healthy subjects from northern China (94 hips; 31 men, 63 women). Three-dimensional CT reconstruction of the proximal femoral medullary cavity was performed using Mimics 22.0 software. The anatomical parameters related to THA were measured to examine the relationships between sex, age, and femoral length. These parameters were compared with previously published data.Results: The internal and external coronal diameters of the femoral medullary cavity, and the anterior and posterior sagittal diameters had different contracting trends. There were correlations between the femoral length, femoral head diameter, and coronal diameter, and between the sagittal diameter and cross-sectional area of the medullary cavity. Age was negatively correlated with the CFI(canal flare index). Sex was correlated with the cross-sectional coronal/sagittal diameters, but not with the canal flare index. The proximal end of the medullary cavity was similar to that reported in Caucasians, but the Asian medullary cavity was narrower distal to the level of the lesser trochanteric line.Conclusions: THA-related anatomy was affected by sex, age, and subpopulation. Compared with sex, age had a greater effect on the fit of the stem to the femoral canal. Each patient must be treated individually, as the anatomical structure varied between individuals.