(See also Overview of Bone Disorders in Children.)
Köhler bone disease is an osteochondrosis, which is a group of disorders of the growth plate of bones that occur when the child is growing rapidly. Doctors are not sure what causes osteochondrosis, but the disorders do seem to run in families. Osgood-Schlatter disease, Legg-Calvé-Perthes disease, and Scheuermann disease are other osteochondroses.
Köhler bone disease is caused by a poor blood supply to the tarsal navicular bone. The poor blood supply causes the tarsal navicular bone to die and collapse. Why the blood supply is poor is not known.
Köhler bone disease usually affects children aged 3 to 5 years (more commonly boys) and typically affects only one foot. The foot becomes swollen and painful, and the arch of the foot is tender. Weight bearing and walking increase discomfort, and the child’s manner of walking (gait) is impaired.
X-rays of the foot show that the navicular bone is initially flattened and hardened and later breaks into fragments before healing and hardening back into bone. X-rays comparing the affected side with the unaffected side help assess how far the disease has progressed.
Köhler bone disease rarely lasts more than 2 years. Rest and pain relief are required, and excessive weight bearing must be avoided. This disease usually resolves without treatment and without any long-term consequences. In severe cases, having the child wear a below-knee walking plaster cast for a few weeks may help. Crutches are often not needed with a walking cast.