Foot Deformities – A Pictorial ReviewNaji Al-Khudairi, Catriona Reid, Fiona Witham and Kiruthika Chandrasekaran

Queen Alexandra Hospital, Portsmouth

Ritchie GW and Keim HA. A radiographic analysis of major foot deformities. Canad Med Ass J Oct 1964; Vol 91.Laor T. Evaluation of pediatric foot radiographs. Cincinnati Children’s Hospital Medical Centre. Power Point.

Radiopaedia online resource.

- The complex terminology associated with congenital and acquired foot deformities can lead to interpretation difficulty and challenges in plain

radiograph reporting.

- Such radiographs have value in providing a record of initial deformity, monitoring progression, and guiding treatment.

- Optimal radiographic interpretation demands accurate and standardised radiographic technique – ‘weight-bearing’ AP ankle, Lateral foot and

ankle, and DP foot views are obtained.

- The aim of this pictorial review is to act as an aide-memoire or reference for the reporter interpreting plain radiographs on congenital and

acquired foot deformities.

Terminology- The complex terminology of foot deformities is best appreciated

by understanding the movements at the main joints of the

foot & ankle.

- Exaggeration of normal movements at these joints produces

a fixed resultant deformity.

-Talipes refers to a congenital foot deformity. Pes refers to an

acquired foot deformity.

Background

Table 1. Terminology of some foot deformities.

Example Cases• Pes Planus:

- Collapse of the longitudinal arch:

Calcaneal Inclination angle (CIa) is the angle measured between the calcaneal

inclination axis and the supporting horizontal surface. Normal 20-30°. Figure 1a.

demonstrates an angle < 20° in pes planus.

Meary’s angle (MEa) is the angle measured between a line drawn through the

longitudinal axis of the talus and the 1st metatarsal. Normal 0°. Figure 1b.

demonstrates an angle 16° convex downwards in pes planus.

- Hindfoot valgus:

Talocalcaneal angle (TaCa) is the angle measured between lines drawn down the

axis of the talus and calcaneus. Normal 25-40°. Figure 1c. demonstrates an angle

50° in pes planus. References

- Tibialcalcaneal angle (TiCa) is

the angle measured between

lines drawn down the axis of the

tibia and calcaneus. Normal 70-

90 degrees. In equinus TiCa >

90 degrees (Figure 3).

Deformity Key FeaturesTalipes equino varus Hindfoot equinus

Hindfoot varusForefoot varus

Talonavicular subluxation

Pes planus Collapse of the longitudinal archHindfoot valgusForefoot abduction

Pes cavus High longitudinal archHindfoot varusForefoot adduction

Figure 1a.WB lateral foot

& ankle. CIa 10°.

Figure 1b.WB lateral foot & ankle. MEa

16°.

-Forefoot abduction:

Talonavicular coverage angle (TNCa) is the angle measured between lines

connecting the edges of the articular surface of the talus and the navicular. It is a

measure of lateral subluxation of the navicular on the talus. Normal < 7°. Figure 1d.

demonstrates an angle 50° in pes planus.

Figure 1c.

WB DP foot. TaCa

50°.

Figure 1d.WB DP foot. TNCa 50°.

- High longitudinal arch:

CIa > 30° in pes cavus (Figure 2a).

MEa 13° convex upwards in pes cavus (Figure 2b).

Figure 2a.WB lateral foot & ankle. CIa 34°.

Figure 2b.WB lateral foot & ankle. MEa 13°.

-Hindfoot varus:

-TaCa < 25° in pes cavus

(Figure 2c).

-Forefoot adduction:

-TNCa normal in this case of pes

cavus (Figure 2d).

Figure 2c.WB DP foot TaCa 10°.

Figure 2d.WB DP foot TNCa <

7°.

• Pes Cavus:

Figure 4a.WB AP ankle.

Figure 4b.WB lateral foot & ankle.

Figure 3WB lateral foot & ankle. TiCa

95°.

• Equinus:• Ball & Socket

Ankle:- Describes a spherical configuration to the

talar dome with corresponding concavity of the

tibial plafond (Figure 4a & 4b). Ankle is in

valgus with lateral subluxation of the

calcaneum relative to the talus. Additionally, in

this case there is an associated talo-calcaneal

bony coalition.