Irreducible ankle fracture-dislocations are very rare entities. The present case report demonstrates an unusual finding of tibialis posterior and flexor digitorum longus tendons interposed in the tibiofibular joint impairing successful closed reduction of ankle fracture-dislocation. A 45-year-old patient presented with a bimalleolar pronation-external rotation ankle fracture-dislocation after a motorcycle accident. Attempts to perform closed reduction before surgery were unsuccessful. Subsequent urgent open reduction and internal fixation surgical management revealed interposition of the tibialis posterior and flexor digitorum longus tendons in the tibiofibular joint. In irreducible fracture-dislocation of the ankle with severe lateral displacement of the talus, one should be aware of the possibility of soft tissue interposition of the tibialis posterior and flexor digitorum longus tendons in the tibiofibular joint.