In 1908, Köhler first described the disease named in his honor.1 This clinical entity belongs to a group of conditions called osteochondroses, which have been reported since 1903. Approximately 40 different osteochondroses are reported in the literature. In these self-limited diseases, there is avascular necrosis of primary or secondary centers of ossification; almost all of the epiphyses, apophyses, and small bones can be implicated.2 The etiology of these conditions is not well known, but vascular accidents, coagulation anomalies, and heredity have been implicated.3 The most common osteochondroses are Legg-Perthes-Calve, Osgood-Schlatter, Sinding-Larsen-Johansson, Kienbock, Freiberg, and Panner diseases.
Kohler’s disease is a condition, where the navicular bone in the foot undergoes avascular necrosis. Avascular necrosis is a disease resulting from the temporary or permanent loss of the blood supply to the bones. Without blood, the bone tissue dies and causes the bone to collapse. For some unknown reason, typically in a child, the navicular bone in the foot loses its blood supply for a while. A common question asked is where is the navicular?
In this uncommon condition, children present with a limp and local tenderness of the medial aspect of the foot over the navicular. The child can walk with an increased weight on the lateral side of the foot. Swelling and redness of soft tissues are frequent.The typical patient is a boy, although it can sometimes happen to a girl. The boy is usually around 5 years old, who complains of pain in the foot over the apex of the longitudinal arch. He walks with a limp, and tends to walk on the outer body of his foot.
It is suggested that the condition may be the result of abnormal strain acting on a weak navicular (the navicular is a bone close to your inner arch). A definitive answer has not been provided. Among the theories to explain the nature of this lesion, a mechanical basis associated with a delayed ossification seems to be the more satisfactory. The navicula is the last tarsal bone to ossify in children. This bone might be compressed between the already ossified talus and the cuneiforms when the child becomes heavier. Compression involves the vessels in central spongy bone leading to ischemia. Ischemia causes clinical symptoms. Thereafter, the perichondral ring of vessels sends the blood supply, allowing rapid revascularization and formation of new bone. The radial arrangement of vessels of this bone is of great importance in explaining why the prognosis of this lesion is always excellent.
What you should do
- Help an overweight child lose weight. Encourage your child to exercise moderately, avoiding extremes.
What you should not do
- Ignore the pain. You cannot grow out of this disease!
What the chiropodist / family doctor will do
Your doctor will order X-rays of both feet to compare them. The affected foot usually has typical findings of a dense flattened navicular bone, compared to the normal foot. Treatment may consist of a walking cast if the pain is severe or an arch support if the pain is less so. Non-steroidal anti-inflammatory medications may help. The child may have to rest from sports for a few weeks till the acute pain is relieved.