Figure 3: Radiographic Image Acquisition. The fixed-flexion weight-bearing stifle radiograph; showing the reference points for measuring joint width and medial and lateral tibiofemoral joint space widths (arrows). Width of the joint was recorded as the average of (a) the maximum width of the proximal tibia and (b) the maximum width of the distal femur. Maximum joint space width was measured as the maximum height of the joint space.