Information on the following diseases can be found in the Related Disorders section of this report:

• Freiberg's Disease
• Gopalan Syndrome
• Tarsal Tunnel Syndrome
• Erythromelalgia

Kohler disease is a rare bone disorder characterized by a painful swollen foot. The foot is especially tender along the length of the arch. Putting weight on the foot or walking is difficult, causing further discomfort and a limp. For reasons that are not understood, the flow of blood to one of the bones in the foot (navicular bone) is interrupted, resulting in progressive degeneration of that bone. In a relative short time, however, the bone heals itself.

Usually, symptoms will be mild, and patients may not seek treatment until the pain and swelling have persisted for a while.

The exact cause of Kohler disease is unknown. It does not appear to be hereditary and, until recently, was not thought to be linked to an injury.

Some orthopedic specialists now believe that Kohler disease may be linked to an injury in the area around a bone (navicular bone) in the foot and may be the result of delayed bone formation (ossification). Structural weakness might result from an increase in the ratio of cartilage to bone. Since the navicular bone is part of the mechanism by which the foot moves (articulation), it is subject to weight-bearing pressures and stresses from twisting and turning.

Under normal circumstances, the navicular bone is served by a blood vessel from which smaller arteries supply blood to the regions of bone growth. At around the ages of foru to six, the blood supply to these regions of bone growth increases as other blood vessels reach them. If ossification is delayed, and the child gains weight, the effect is to compress the blood vessels, thus causing tissue destruction (ischemia).

Kohler disease is a rare bone disorder of the foot that affects males more often than females. The disorder strikes children between the ages of 1 and 10 years with a peak occurring at ages 3 to 7 years. The center of bone growth that is affected in Kohler disease develops in young girls about one year before it appears in young boys. Nevertheless, the disorder is five times more prevalent in boys than girls.

It is thought that the incidence of the disorder in the population is about 2%.

Freiberg's Disease is a rare bone disorder characterized by a painful foot which is especially tender toward the front. Putting weight on the foot or walking can cause further discomfort. Progressive degeneration (osteonecrosis) of part of one of the long bones in the foot (head of second metatarsal) causes the symptoms to develop. Surgery may be necessary to treat this disorder. (For more information on osteonecrosis, choose "osteonecrosis" as your search term in the Rare Disease Database.)

Gopalan Syndrome, which is characterized by burning sensations in the feet, is thought to be caused by a possible deficiency of a B Vitamin (pantothenic acid). Severe burning, aching and cramp-like pains in the soles of the feet (and possibly palms of the hands) can occur. Often, patients experience a sensation like pins and needles in the feet.

Tarsal Tunnel Syndrome involves pressure on nerves to the foot causing pain. The initial symptoms of Tarsal Tunnel Syndrome are swelling of the feet, and painful burning, tingling or numb sensations in the lower legs. Symptoms can become more intense and extend to leg muscles after standing for long periods during the day. These symptoms usually diminish with successful treatment. (For more information on this disorder, choose "Tarsal Tunnel Syndrome" as your search term in the Rare Disease Database.)

Erythromelalgia is a syndrome of sudden intense dilation of blood vessels (paroxysmal vasodilation). This causes intense burning pain, increased skin temperature, and redness of the feet and, less often, the hands. (For more information on this disorder, choose "Erythromelalgia" as your search term in the Rare Disease Database.)

Diagnosis
Kohler disease is diagnosed with an X-ray of the foot and the presence of weight-bearing pain in the middle of the foot.

Treatment
Treatment ranges from weight-bearing short-leg plaster casts at one extreme to "watchful waiting" at the other. Special supportive shoes may also be considered. Staying off the foot as much as possible helps in recovery. Symptoms can last for a few days or persist for up to two years. However, symptoms usually resolve within a year.

TEXTBOOKS
Myerson MS. Foot and Ankle Disorders. WB Saunders Co., Philadelphia, PA. 2000:793-96.

Cook RA, O’Malley MJ. Navicular Osteochondritis (Kohler Disease). In: NORD Guide to Rare Disorders. Lippincott Williams & Wilkins. Philadelphia, PA. 2003:21.

Beers MH, Berkow R., eds. The Merck Manual, 17th ed. Whitehouse Station, NJ: Merck Research Laboratories; 1999:2414-15.

REVIEW ARTICLES
Harty MP. Imaging of pediatric foot disorders. Radiol Clin North Am. 2001;39:733-48.
Toth AP, Easley ME. Ankle chondral injuries and repair. Foot Ankle Clin. 2000;5:119-33.

Bui-Mansfield LT, Lenchik L, Rogers LF, et al. Osteochondritis dissecans of the tarsal navicular bone: Imaging findings in four patients. J Comput Assist Tomogr. 2000;24:744-47.

JOURNAL ARTICLES
Tsirikos AI, Riddle EC, Kruse R. Bilateral Kohler’s disease in identical twins. Clin Orthop. 2002;409:195-98.

Gips S, Ruchman RB, Groshar D. Bone imaging in Kohler’s disease. Clin Nucl Med. 1997;22:636-37.

FROM THE INTERNET
Vargas-Barreto B. Kohler Disease. eMedicine. Last Updated: May 22, 2002:5pp.
www.emedicine.com/orthoped/topic410.htm

Questions and Answers About Avascular Necrosis. National Institute of Arthritis and Musculoskeletal and Skin Diseases. NIAMS. Publication Date: January 2001. 7pp.
www.niams.nih/gov/hi/topics/avascular_necrosis/index.htm

Kohler’s disease. Gpnotebook. 2003:1p.
www.gpnotebook.co.uk/cache/-1241120759.htm


KOHLER'S DISEASE OF THE TARSAL NAVICULAR. G. A. Williams and H. R Cowell; Clin Orthrop (Jul-Aug 1981; issue 158). Pp. 53-58.

KOHLER'S DISEASE OF THE TARSAL NAVICULAR: LONG-TERM FOLLOW-UP OF 12 CASES. E. Ippolito, et al.; J Pediatr Orthop (Aug 1984; issue 4 (4)). Pp. 416-417.

KOHLER'S OSTEOCHONDROSIS OF THE TARSAL NAVICULAR: CASE REPORT WITH TWENTY-EIGHT YEAR FOLLOW-UP. K. M. Devine and R. E. Van Demark, Sr.; S D J Med (Sep 1989; issue 42 (9)). Pp. 5-6.