Fig. 2

a Measurement methods for the distance from the medial tibial eminence (MTE) to the medial femoral condyle (MFC) and the femorotibial angle (FTA) during weight bearing with the knee flexed at 45°. The MTE line (a) and MFC line (b) are drawn perpendicular to the line tangent to the medial and lateral femoral condyles, along the lateral edge of the MFC. The distance between the MTE and the MFC is then measured (white double-headed arrow). b Measurement of the medial joint space (MJS) width using the Rosenberg view. The MJS is measured from the center of the MFC to the center of the medial tibial plateau (white double-headed arrow). The weight-bearing FTA, with the knee flexed at 45°, is measured (black lines) (a). A best fit line is drawn through the midpoints of the outer cortex of both the femur and tibia, and the FTA is defined by the angle at their intersection