Kohler disease is an uncommon, painful bone disorder of a child’s midfoot most commonly seen in children between 2 and 9 years of age. It was first described in 1908 by a Dr. A. Kohler, a radiologist, who noted in children with foot pain some characteristic x-ray findings that showed irregularity in the growth and development of the navicular bone in the foot.
Kohler disease affects boys 5 times more often than girls and typically, just one foot is affected.
What causes Kohler Disease?
Kohler disease belongs to a group of conditions called osteochondroses. Osteochondroses are disturbances of bony growth at ossification centres that occurs during times of great developmental activity.
The navicular bone is the last bone in the foot to ossify (turn from soft cartilage into bone). This ossification process usually happens between the ages of 18months to 2yrs in girls and a little later in boys, between 2.5 and 3 years.
It is thought that if the navicular bone ossifies a little later than usual, the softer bone is affected by weight bearing pressures and stresses caused by repeated running, jumping, hopping and skipping. This compression or strain injury to the soft bone causes a temporary loss of blood supply to the developing navicular bone resulting in an avascular necrosis of the growth centre in the bone.
What are the symptoms of Kohler disease?
Most children with Kohler disease present with a limp and may walk on the outside border of the foot to relieve pressure on the arch area. There can be pain, swelling, redness or warmth on the top and inner side of the foot. The diagnosis is confirmed by x-ray and physical examination.
Symptoms can last for a few weeks or may persist for up to 2 years. Once the acute inflammation resolves, the body starts to heal the affected bone and the navicular regains its size, density and structure.
How is Kohler disease treated?
Treatment aims to reduce the pain and inflammation, diminish a limp and allow the child to ambulate without pain. Children experiencing moderate to severe pain may require temporary immobilization with the use of a removable walking boot / cast for a few weeks or months. Most children will require the use of foot orthoses placed inside a stable shoe to help reduce the weight bearing pressure on the navicular bone, until the bone recovers. Bone healing may take from as little as a few months or, in some cases, up to 2 years.
Surgery is not indicated in the treatment of Kohler disease.