Lateral talocalcaneal angle

The lateral talocalcaneal angle is one of the angles that can be measured for the assessment of pes planus and pes cavus and assessment of hindfoot deformity.

Measurement

The lateral talocalcaneal angle is drawn on a weight-bearing lateral foot radiograph. There are two ways that it has been defined ²:

• the angle between the calcaneal inclination axis and the mid-talar axis
• the angle between the lines bisecting the longitudinal axis of the two bones

The calcaneal inclination axis is generally more easily measured than the longitudinal axis of the calcaneus. It tends to be steeper and therefore the angle measured against the calcaneal inclination axis will be greater than using the mid-calcaneal axis.

Interpretation

The lateral talocalcaneal angle should normally measure between 25 and 40°:

• <25°
  • hindfoot varus
  • congenital talipes equinovarus (clubfoot)
  • pes cavus
• >40°
  • hindfoot valgus
  • congenital verticle talus
  • skewfoot deformities
  • pes planus