Calcaneal apophysitis is a relatively common disease in young athletes. On the other hand, if not treated properly, it can lead to apophyseal avulsion fracture in rare cases. In the case of apophyseal avulsion fractures, it is often necessary to remove or preserve the bone fragment, which often requires a suture of the Achilles tendon. A 10-year-old badminton athlete visited the outpatients’ clinic with pain in both heels from 10 months ago without any trauma history. After conservative therapy, the pain in the left heel was relived but the right heel pain persisted. After 10 months of conservative therapy, the patient visited the outpatients’ clinic showing a calcaneal apophyseal avulsion fracture with a total rupture of the Achilles tendon. In the operation room, a bone fragment needed to be removed because of its poor viability and the fragment was too thin for fixation. After removing the bone fragment, the ruptured Achilles tendon was fixed with an anchor system.