Fig 2.

The patient is lying in the supine position. The knee flexion angle is assessed by evaluating whether the desired angle is correct. For this verification, we recommend taking a lateral photograph of the knee and measuring the knee angle with the Bone Ninja application (A), or a traditional goniometer can be used (B, C). In panel A, the blue line represents the center of the long axis of the femur viewed in lateral view. The red line represents the center of the long axis of the tibia viewed in lateral view. In panel C, the blue oval represents a zoom of the numerical representation of the measured angle.