Table 2 Definitions of the parameters used to describe the morphology of the ankle joint

Distal tibia

 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)

Antero-posterior gap supero-inferior component of the distance between A and B

 APA (deg)

Antero-posterior inclination angle inclination angle between the antero-posterior 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)

Supero-inferior distance between A and C

 MDV (mm)

Supero-inferior distance between the most proximal vertex of the tibial mortise (V) and the point D

 TiW (mm)

Tibial width medio-lateral distance of the tibial mortise calculated using the two end-points of the anterior and posterior edges

 MalW (mm)

Malleolar width medio-lateral 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 medio-lateral 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

 TaW (mm)

Trochlea tali width width between medial and lateral crests of the talar dome

 TaR (mm)

Trochlea tali radius radius of the talar dome in the sagittal plane, as identified by the arc FG

 MLATa (deg)

Angle in the frontal plane between the medio-lateral axis and the line joining the two most proximal vertices of the trochlea tali