Definition of a Novel Proximal Femur Classification in the Sagittal Plane According to the Femur Morphometric Analysis

Background Studies on prosthesis positioning and implant design in total hip arthroplasty (THA) have generally focused on the anatomy of the proximal femur in the coronal plane. The aim of this study was to investigate the proximal femur morphology in the sagittal plane to provide better positioning of the femoral component in THA and contribute to the determination of proximal femur morphology through possible outcomes that can be shown also by considering the sagittal plane in the selection and design of the femoral component. Methods Computerized tomography scans were obtained from 270 femoral bones belonging to adult skeletons, followed by 3D reconstruction using Leonardo Dr/Dsa Va30a software (Siemens, Erlangen, Germany) and measurements. Canal widths were measured in the coronal and sagittal planes at the lesser trochanter (LT) level, at 20 millimeters proximal to the LT(LT+20) and at various levels distal to the lesser trochanter in 25 mm jumps up to 200 mm from the lesser trochanter. Results The average width was wider at the level of the lesser trochanter and all points distal to it in the sagittal plane compared to the coronal plane except LT−200 mm. At each levels from LT−25 to LT−175, the differences were statistically significant (P < .05). The ratio of the femoral width at the lesser trochanter level to the width 50 mm distal to the LT was stated as the most prevalent one, and a novel classification in the sagittal plane was developed in accordance with these findings. Conclusion A novel and simple classification in the sagittal plane was developed based on the findings of this study, and this classification may improve the accuracy, validity, and reliability of femoral stem fixation in total hip arthroplasty.