Tehran University of Medical Sciences Journal of Orthopedic and Spine Trauma 2538-2330 11 4 2025 12 02 170 6 Jeevan A Junior Resident, Department of Orthopedics, GMERS Medical College Gotri, Vadodara, India Ruchit Vyas Senior Resident, Department of Orthopedics, GMERS Medical College Gotri, Vadodara, India Mukesh Dwivedi Professor, Department of Orthopedics, GMERS Medical College Gotri, Vadodara, India Tarun Desai Associate Professor, Department of Orthopedics, GMERS Medical College Gotri, Vadodara, India Bharat Soni Senior Resident, Department of Orthopedics, GMERS Medical College Gotri, Vadodara, India Fenil Shah Junior Resident, Department of Orthopedics, GMERS Medical College Gotri, Vadodara, India Prashant Alwani Assistant Professor, Department of Orthopedics, GMERS Medical College Gotri, Vadodara, India Ammar Rampurwala Senior Resident, Department of Orthopedics, GMERS Medical College Gotri, Vadodara, India Chirag Thakkar Professor, Department of Orthopedics, GMERS Medical College Gotri, Vadodara, India 2025 03 19 2025 12 01 Background: Diaphyseal humerus fractures are frequent orthopaedic injuries requiring effective management for optimal recovery. This study aims to evaluate and compare the outcomes of open reduction with dynamic compression plating (DCP) and closed reduction with flexible intramedullary nailing (IMN) for treating humeral shaft fractures. Methods: This prospective, randomized study included 50 patients with diaphyseal humeral fractures, randomized to either DCP (group P) or IMN (group N). Primary outcomes assessed were radiological union, functional recovery through Disabilities of the Arm, Shoulder, and Hand (DASH) scores, and range of motion (ROM). Secondary outcomes included surgical duration, exposure to radiation, and postoperative complications. Results: The union rate was comparable between the two groups, with 100% in group P and 96% in group N (P = 0.99). Similarly, the DASH scores showed no significant difference (group P: 21.80  ±  6.98, group N: 24.56  ±  9.48, P = 0.24). Group P required longer surgical time and showed higher chances of surgical site infection (SSI), while group N experienced higher exposure to radiation and increased implant-related complications. Conclusion: Both DCP and flexible IMN are viable options for diaphyseal humerus fractures, with no significant difference in functional outcomes. The choice between these methods should consider patient-specific needs and fracture characteristics. https://jost.tums.ac.ir/index.php/jost/article/view/665 https://jost.tums.ac.ir/index.php/jost/article/download/665/445