Fig. 1

a The angle-measuring instrument attached to the handle of the femoral broach. b The angle of the angle-measuring instrument. The angle of the angle-measuring instrument was measured as the angle between the gravitational direction and the line running perpendicular to the prosthetic axis under 90° hip flexion, maximum hip adduction, and 90° knee flexion, with the tibia in a vertical position. α° represents the anteversion of the femoral broach and stem. c Anteversion of the femoral broach and stem. When the tibia was placed in a vertical position, the axis passing through the medial and lateral femoral condyles ran perpendicular to the gravitational direction. The anteversion of the femoral broach and stem was determined as the angle between the prosthetic axis and the line running perpendicular to the gravitational direction. The anteversion of the femoral broach and stem reflected the angle between the gravitational direction and the line running perpendicular to the prosthetic axis. α° indicates the anteversion of the femoral broach and stem