Coronal plane stability of cruciate-retaining total knee arthroplasty in valgus gonarthrosis patients: A mid-term evaluation using stress radiographs

Figure 3 Measurement methods used in this study. A: The valgus gap opening distance was measured by subtracting the medial gap from the lateral gap on the stress radiograph; B: The valgus gap opening angle was determined based on the angle between the line of the tibial tray and the line of the most distal part of the femoral component on the stress radiograph; C: The varus gap opening distance was measured by subtracting the lateral gap from the medial gap; D: The varus gap opening angle was determined based on the angle between the line of the tibial tray and the line of the most distal part of the femoral component; E: The alpha (α) and beta (β) angles of the femoral and tibia components on the antero-posterior radiograph.