Fig 1.
A: The ankle in AP view, TPI is the angle between the tibial plafond (a) and the floor (c). The TT is measured between the tibial plafond (a) and the talar dome (b). B: The foot and ankle in lateral view, the lateral talo-first metatarsal angle is the angle between the longitudinal axis of the talus (d) and the first metatarsal (e). The naviculo-cuboid overlap is the overlapped portion between the navicular and cuboid (f) divided by the vertical height of the cuboid (g). C: The mechanical tibiofemoral angle is the angle between the mechanical axis of the femur (h) and that of the tibia (i).
Fig 2.
Two types of medial ankle osteoarthritis.
A: The varus angulation type is defined as a TT ≥ 4°. B: The medial translation type as TT < 4°.
Table 1.
Comparison of variables between the varus angulation and the medial translation groups.
Table 2.
Correlation coefficients between the radiographic measurements.
Table 3.
Significant factors discriminating between the varus angulation and medial translation groups in medial ankle osteoarthritis.
Fig 3.
The mTFA of the varus angulation type tends to be distributed in the genu valgum to a greater extent compared to that of the medial translation type.
Fig 4.
In patients with rigid foot varus deformities, corrective osteotomy of the distal tibia to a more valgus alignment can paradoxically aggravate ankle varus incongruency or TT because the foot cannot compensate and adapt to changes in mechanical alignment.