An avulsion fracture of tibial tuberosity with an unusual articular involvement was treated with open reduction and internal fixation. Although the mechanism of tibial tuberosity fracture is described as passively flexing the knee while active quadriceps femoris contraction, the weight transmitted from the menisci on the lateral side of the knee joint may cause an epiphyseal disruption. We report a case of tibial tuberosity fracture with lateral plateau rim fracture in a young male adolescent, which has not been published previously in the literature.