Table 2 Definitions of the ankle morphological parameters

TiAL (mm)

Tibial arc length: distance between the most anterior (A) and posterior (B) points of the maximal arc of the tibial mortise in the sagittal plane

TiSR (mm)

Tibial sagittal radius: radius of the AB arc

APG (mm)

Anterio-posterior gap: longitudinal (Y-axis) component of the distance between A and B

APA (deg)

Anterio-posterior inclination angle: inclination angle between the X-axis and the AB segment

MTiTh (mm)

Maximal tibial thickness: The A/P distance from the most anterior (C) to the most posterior (D) point on the tibial profile in the sagittal plane

MDA (mm)

Longitudinal (S/I) distance between A and C

MDV (mm)

Longitudinal (S/I) distance between the most proximal vertex of the tibial mortise (V) and the point D

TiW (mm)

Tibial width: M/L distance of the tibial mortise calculated using the two end-points of the anterior (TiWa) and posterior (TiWp) edges

MalW (mm)

Malleolar width: M/L distance between the most lateral point of the fibula and the most medial point of the tibia

MLATi (deg)

Angle in the frontal plane between the M/L axis and the line joining the most distal points of the fibula and tibia

Talus

TaAL (mm)

Trochlea tali arc length: distance between the most anterior (F) and posterior (G) and proximal (H) points of the trochlea tali, as seen in the sagittal projection of the talus. The suffixes m, l and c indicate the corresponding medial, lateral and central arcs, respectively

TaW (mm)

Trochlea tali width: width between medial and lateral crests of the talar dome. The suffix a, p and c indicates this width, respectively, in the most anterior, most posterior and central location along M/L axis, i.e., of Fm F _l , G _m G _l and H _m H _l segments

TaR (mm)

Trochlea tali radius: radius of the talar dome in the sagittal plane, as identified by the arc GF. The suffixes m, l and c indicate the corresponding medial, lateral and central arcs

MLATa (deg)

Angle in the frontal plane between the M/L axis and the line joining the two most proximal vertices of the trochlea tali