Fig. 3

Radiographic measurements of morphometric parameters on whole-leg anteroposterior weight-bearing radiographs. Line (a) represents the mechanical axis of the tibia, (b) the subchondral plate of the distal tibial articular surface, (c) the subchondral plate of the medial malleolus articular surface, and (d) the line connecting the tips of both malleoli. The tibial anterior surface angle (TAS) is defined as the angle between lines (a) and (b), the tibial medial malleolus angle (TMM) is the angle between lines (a) and (c), and the tibial bimalleolus angle (TBM) is the angle between lines (a) and (d)