Background: The treatment of the third malleolus has evolved in recent years, and surgical treatment can be carried out with traditional percutaneous osteosynthesis using anteroposterior screws or ORIF with a posterolateral plate. Methods: Our study included 54 patients divided into two groups based on the intervention type (screw or plate). Instrumental assessments comprised pre- and post-operative X-rays and pre-operative CT scans to evaluate joint step-off. The mean follow-up duration was 1 year and 9 months. Results: Radiographic control revealed no loss of reduction or mobilization of the synthesis devices, and all patients achieved fracture healing. Articular step-off > 2 mm was observed in 21 patients (38.9%), including 4 in the plate group and 17 in the screw group, with a statistically significant likelihood of step-off presence in the latter. The mean AOFAS score was 90 points, negatively correlated with age, and lower in patients with joint step-off and a 15° reduction in ROM. Conclusions: The management of posterior malleolus fractures has changed with anatomical studies and an understanding of ankle stability through CT scans. ORIF with a posterior plate is advantageous for anatomical reduction of the tibial plafond but is disadvantageous in terms of surgical invasiveness and technical difficulty.