Fig. 2

Diagram illustrating the measurement of the implantation parameters for the TKA femoral component. a The flexion angle (in the sagittal plane) of the femoral component (α angle). Line a is the femoral shaft axis; line b lies along the bottom of the femoral implant. b The valgus angle (in the coronal plane) of the femoral component (β angle). Line a’ is the anatomic axis of the femur; line b’ is the mechanical axis of the femur. c The external rotation angle (in the axial plane) of the femoral component (γ angle). Line a” is the transepicondylar axis; line b” is parallel to the transepicondylar axis; and line c” is the posterior condylar line of the femur