Medical Therapy
A walking short leg cast with toe extension is recommended. Total cast time is approximately 6-8 weeks. The cast is better in moderate varus (10-15º) that is associated with moderate equinus (10-20º). In this position, the navicular is relaxed from posterior tibialis strain. Arch supports can be prescribed after the cast period and used for an average of 6 months. In mild cases, soft arch supports may be the only treatment necessary.
Surgery is not indicated for Köhler disease.
Complications
In 1984, Ertel and O'Connell reported a case of acquired talonavicular coalition that followed avascular necrosis (AVN) of the tarsal navicular bone. [14] This complication is very rare.
Long-Term Monitoring
In treated patients, symptoms may last less than 3 months. [10] In untreated patients, symptoms may be present for 15 months. Because immobilization in a short leg cast decreases the duration of symptoms, treating all patients for at least 6 weeks is recommended.
If pain persists after a 6-week period of casting, a new cast must be applied for 6 supplementary weeks. [15] If pain does not disappear after the cast period, other causes of foot pain, including talar coalition or an accessory navicular, should be investigated. [16]
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Radiograph from 16-year-old patient who had Köhler disease. Normal x-rays at adulthood are the rule for Köhler disease.
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Radiograph from patient with Köhler disease. Image is typical for this disease. Note flat aspect of tarsal scaphoid.