BACKGROUND Lateral malleolus fractures, typically from trauma, sports, or accidents, are common, with supination external rotation (SER) injuries being most prevalent. SER injuries involve complex joint mechanics and often necessitate surgical intervention for instability. This study compares intramedullary nail and plate fixation for fibula fractures in SER type IV ankle injuries, considering their biomechanical properties and influence on fracture healing. MATERIAL AND METHODS A prospective, randomized study was conducted between January 2021 and December 2021. A total of 81 patients with SER injuries were included in the study. Surgical procedures were performed using either intramedullary nails or plates. The following parameters were recorded and analyzed: postoperative complications, operation times, bone healing times, American Orthopaedic Foot & Ankle Society (AOFAS) scores, visual analog scale (VAS) scores for pain, and ankle range of motion. RESULTS Out of the 81 cases, 42 were treated with intramedullary nails, while 39 received plate fixation. Statistical analysis revealed a significantly lower rate of postoperative complications in the intramedullary nail group than in the the plate fixation group (9.52% vs 30.77%, P<0.0164). However, there were no significant differences between the 2 groups in terms of operation time, bone healing time, AOFAS scores, VAS scores, and functional evaluations (P>0.05). CONCLUSIONS Plate fixation and intramedullary nail fixation are effective techniques for treating fibula fractures in SER type IV injuries. However, intramedullary nail fixation demonstrates a lower rate of complications. Therefore, intramedullary nails may be preferable to plate fixation for the management of fibula fractures in SER type IV ankle injuries.