The menisci are the essential structures of the knee joint because they disperse body weight and reduce friction during the movement. An avulsion fracture of the posterior medial meniscus root, also known as meniscal ossicles, can lead to meniscal extrusion. Consequently, the medial meniscus loses its ability to absorb hoop stress. One patient presented with nonunion posterior root avulsion fracture of the medial meniscus concomitant with posterior cruciate ligament (PCL) injury. The patient underwent arthroscopic suture repair through the placement of a tibial tunnel 1 year after injury. The fracture united well, and complete recovery was achieved at the 2‑year follow‑up. To the best of our knowledge, this is the first report describing a posterior root avulsion fracture of the medial meniscus with concomitant PCL avulsion fracture.