Concomitant fractures of the inferior and medial orbital wall can cause more severe orbital symptoms and lead to incomplete reduction postoperatively. This report presents the case of a 17-year-old boy, presenting with persistent diplopia and enophthalmos after floor reduction for concomitant fractures. At the time of the fracture, surgery was performed for only the orbital floor by a plastic surgeon, because the medial wall fracture was minimal. However, he presented with persistent orbital symptoms after surgery. An aggravated medial wall fracture was discovered via computed tomography (CT) examination. It was treated with a minimal-invasive method using an endoscopic approach.