Radiographic assessment of leg alignment and grading of knee osteoarthritis: A critical review

Figure 1 Diagram of a varus knee illustrating the mechanical and anatomic axes and angles. The FS-TS angle is 4° to 6° valgus compared to the HKA angle. (Modified from Cooke and Sled[46]). FM: Femoral mechanical axis; TM: Tibial mechanical axis; FA: Femoral anatomic axis; TA: Tibial anatomic axis; HKA: Hip-knee-ankle angle (mechanical angle); FS-TS: Femoral shaft-tibial shaft angle (anatomic angle).

Figure 2 Calibrated template, used to position feet and to reliably measure lower extremity rotation. (Modified from Orthopedic Alignment and Imaging Systems, Inc.)

Figure 3 Knee radiograph assessed with representative global, composite and individual feature osteoarthritis grading scales. The knee is in neutral rotation and slight varus alignment. The medial tibiofemoral compartment is most-affected. OA: Osteoarthritis.