Köhler disease is avascular necrosis of the navicular bone, commoner in boys between the ages of 4 and 6 years. It is typically a self-limiting condition.

This condition is believed to be due to a mechanical cause from delayed ossification. The navicular is the last tarsal bone to ossify which may get compressed between the already ossified talus and cuneiforms as the child grows. Hence, the navicular blood supply is susceptible to compressive ischemia leading to avascular necrosis. The prognosis is excellent due to the radial pattern of blood supply to the navicular bone ¹.