מחלת העצם של קוהלר

This is defined as osteochondrosis of the tarsal navicular bone.

What is Köhler's disease?¹

Köhler's disease is part of a group of diseases called osteochondroses, which are noninflammatory, noninfectious derangements of bony growth at various ossification centres occurring during times of great developmental activity. They affect the epiphyses.

Other osteochondroses include:

• מחלת פרייברג - head of 2nd metatarsal.

• מחלת פנר - capitulum.

• מחלת בלונט - proximal tibia.

• מחלת סבר - calcaneus.

• Sinding-Larsen and Johansson syndrome - patella.

אטיולוגיה

The aetiology of Köhler's disease is unknown, but it is thought to be caused by the compression of the navicular bone prior to ossification. This leads to blood flow abnormalities resulting in avascular necrosis.²

How common is Köhler's disease? (Epidemiology)

Köhler's bone disease is rare.

• It commonly affects children aged 3 to 5 years old, but is seen any time between age 2 and 10 years.³

• It is more common in boys; however, girls with this condition are often younger than boys with the disease.² This is probably due to the onset of ossification in girls, which occurs at age 18-24 months. In boys, ossification occurs at age 24-30 months.

Köhler's disease presentation

Children present with:¹

• A unilateral antalgic gait (a limp, avoiding putting weight on painful structures)

• Local tenderness of the medial aspect of the foot, over the navicular bone

The child is able to walk by taking the majority of their weight on the lateral aspect of the foot. Frequently, there is swelling and redness of the soft tissues.

חקירות

Plain X-ray

X-rays comparing the affected with the unaffected side help assess progression.

• The navicular bone is initially flattened and sclerotic. Later it becomes fragmented and then re-ossifies.⁴

• The lateral view shows a flat tarsal scaphoid.

• The space between the talus and the cuneiforms is preserved.

MRI/CT scanning

This is used if pain persists 6 months after casting. This is necessary to exclude a tarsal coalition. This is when the bones fuse and is a frequent cause of painful flatfoot in the older child or adolescent.

Köhler's disease treatment and management¹

Treatment options include rest, ice, and immobilisation in a walking cast for four to six weeks.

If pain persists after a 6-week period of casting, a new cast must be applied for 6 supplementary weeks.

Other causes of foot pain (including talar coalition or an accessory navicular) should be excluded if the pain does not disappear despite immobilisation.

תחזית

Symptoms in treated patients can last for less than 3 months. The course is otherwise chronic, but rarely lasts longer than 3 years.⁴