What is it ?
A tarsal coalition is a condition of the foot in which two bones are abnormally connected by either fibrous, cartilage or bony tissue resulting in abnormal biomechanics of the foot. Many cases are asymptomatic but children and adolescents may present with a painful foot and flattening of the arch.
Who Gets it ?
Tarsal coalition may be inherited (autosomal dominant with variable penetration). As many cases are asymptomatic the true incidence is unknown but probably of the order of 10% of the population. The most common coalitions are calcaneo-navicular and talo-calcaneal although almost any foot bone may be affected.
What is the natural history ?
The majority of painful coalitions can be managed by appropriate conservative treatment but some degree of foot stiffness will persist. Those coalitions that continue to produce pain despite best treatment usually require removal.
How do you treat it ?
It is important that a firm diagnosis is made both clinically and with cross sectional imaging by with CT or MRI. If immobilisation, injection and physiotherapy fail to relieve symptoms the coalition is surgically removed and a graft of fat placed in the defect to stop regrowth of bone. Some patients may require correction of secondary foot deformities as part of the treatment.