Fractures of the fabella are rare, with only nine cases reported in the literature. However, they can cause severe posterolateral knee pain. Other complications include osteoarthritis and, very rarely, peroneal nerve compression. All the prior cases have been transverse fractures. Here we present a first case of a sagittally oriented fabella fracture initially diagnosed on radiographs and subsequently confirmed by computed tomography (CT) with three-dimensional volume renderings. Early recognition and conservative treatment with rest, immobilization, and physical therapy are believed to be effective at relieving symptoms.