ROCKERBOTTOM FOOT (VERTICAL TALUS)

 
Normal Foot - a line projected thru longitudinal axis of talus falls to dorsal side of navicular on maximum plantar flexion lateral view.
Rockerbottom foot - key feature of fixed dorsal dislocation of naviclar on neck of talus, equinus ankle contracture, and abduction contracture of the foot
Diagnosis is confirmed by lateral x-ray in maximum plantarflexion, which demonstrates the irreducible talonavicular joint, and in maximum dorsiflexion, which demonstrates fixed equinus; plantar flexion fails to realign talus & first metatarsal, confirming diagnosis of a fixed talonavicular dislocation ("vertical talus");

ULTRASOUND

• Vertically orientated talus with an increased talocalcaneal angle.
• Dorsal navicular dislocation at the talonavicular joint.
• Heel equinus.

ASSOCIATED DISORDERS

• Arthrogryposis multiplex congenita.
• Trisomy 13.
• Trisomy 18.
• Spina bifida.