Ct images of the talo-calcaneal tarsal coalition.
Tarsal coalition takedown-Pre operative CT scan
A bony Tarsal coalition is best imaged using a CT scan which will confirm the diagnosis(here a talo-calcaneal coalition ,1) and provide a route map for the surgery. The coalition is best regarded as a "field defect" with patent articular surfaces often being hypoplastic and characteristic talo-navicular spurring(2,which may also be excised).
A tarsal coalition may be fibrous(and so not seen on plain Xray or CT) in which case MRI will be of use.