Up to now there was no publication describing a combined instability of the calcaneocuboid and lateral ankle joint. A 38 years old teacher (a former gymnast) complained about increasing giving way symptoms and pain at the lateral foot and ankle. Because of this, he was unable to take part in sports activities. Clinical investigation revealed lateral ankle and calcaneocuboid joint instability. Surgical treatment was done using periosteal flap augmented capsular reefing for both joints, resulting in full ability in sport and profession four months later.