Navicular is medially displaced, articulating with the medial surface of the head of talus. Calcaneus bone is adducted and its anterior portion lies under the head of the talus.
After locating the head of talus, which acts as a fulcrum of correction, the foot was abducted beneath the stabilized talar head.
Tenotomy is indicated when HS > 1, MS < 1 and head of talus is covered.
Pirani Score Deformity Present and Mild Absent fixed (1) (0.5) (0) Hind-foot deformities Posterior heel crease 1 0.5 0 Empty heel 1 0.5 0 Rigidity of equinus 1 0.5 0 Mid-foot deformities Curvature of lateral border 1 0.5 0 of foot Medial crease 1 0.5 0 Lateral head of talus 1 0.5 0 Total score Table 2.
Three clinical symptoms for midfoot included curved lateral border, medial crease and lateral position of head of talus
. Three clinical symptoms for hindfoot included posterior crease, rigid equines and empty heel.
In the anterior one third of superior surface of calcaneum there are two articular facets- anterior and middle for the articulation of head of talus
.  The posterior calcaneal facet for talus does not show much variation.
Medial subluxation of the navicular on the head of talus
and there can be internal tibial torsion and cavus.