Posterior malleolus fractures are frequent injuries, present in 7---44% of all ankle fractures. The objective of this study is to review the evidence to indicate the fixation of this fracture and to choose the appropriate surgical approach. The classic indications for fixation were fragment size greater than 25---30% of the articular surface and displacement greater than 2 mm. However, current evidence suggests that, rather than size, factors such as syndesmotic instability, intra-articular step-off greater than 1---2 mm, plafond impaction and the presence of intercalary fragments should be considered. When comparing the different surgical approaches, the literature supports the use of posterior approaches and reserves the recommendation of the traditional approach for exceptional cases. For the treatment of this injury it is essential to know the anatomy of the ankle and to consider all the factors described above, in addition to the presence of concomitant injuries.