The indication for surgical treatment of posterior ankle fractures is to consider surgical fixation if the entire fracture mass, involving more than 1/4 of the posterior ankle area, is significantly misaligned and causes unevenness of the joint surface, which is most often considered for screw or plate fixation. If the fracture is large or causes unevenness of the joint surface, it may cause instability of the ankle joint or traumatic arthritis. Therefore, in such cases, the joint surface should be repaired surgically to restore the stability of the joint and to avoid the complications of ankle instability and traumatic arthritis caused by the fracture. The entire surgical indications need to be determined by a combination of radiographs and CT examinations to clarify the characteristics of the fracture and select the appropriate treatment plan.