Fig. 9

Stage 3b osteoarthritis of the left ankle in a 74-year-old woman. a Stage 3b osteoarthritis on weightbearing frontal radiograph. b Anterior subluxation on weightbearing lateral radiograph. c Joint space obliteration on sagittal simulated weightbearing computed tomography (SW-CT). d, e, f On coronal SW-CT, joint space obliteration is widespread at the anterior distal articular surface of the tibia (d) but is narrower across the center (e) posteriorly (f). g All sections were mapped in the articular surface of the medial malleolus, by mapping result of SW-CT as in Fig. 9d, e, f. h Four sections on the anterior row, three sections on the central row, and one section on the posterior row were mapped in the distal tibia articular surface by mapping result of SW-CT as in Fig. 9d, e, f