Traditionally, posterior malleolus fractures have been indicated for fixation based on the size of the fracture fragment. More recently, studies have shown that the need for fixation is based on the amount of articular displacement rather than the size of the fracture fragment. Accurate reduction of the posterior malleolus, including the incisura, is important for syndesmotic stability and optimal contact pressure within the ankle joint. Posterior malleolus fractures often are managed with the use of a buttress plate and articular lag screws via an open or percutaneous approach. The posterolateral approach allows access to the posterior and lateral malleolus fractures via a single incision. An open approach also facilitates removal of interposed soft tissue or loose osseous fragments and direct visualization of reduction. This is important in patients with small or comminuted fractures that are difficult to manage percutaneously. This video reviews the diagnostic workup and management of trimalleolar fracture-dislocations, including indications for temporizing fixation with the use of an external fixator before definitive fixation. Indications for the posterolateral approach, preoperative and postoperative imaging studies, the surgical technique for the posterolateral approach, and a review of the outcomes and complications of the posterolateral approach reported in the literature are discussed. Postoperatively, the ankle of the patient shown in this video was placed in a splint, and the patient was instructed to remain non–weight bearing for 6 weeks. At 6 months postoperatively, the fracture had healed and the patient had returned to baseline ambulatory activity with no restrictions.