ObjectiveThis study aims to evaluate the results of intramedullary nail treatment in surgical treatment of adult displaced radius and ulna diaphyseal fractures.Patients and methodsEighteen patients (36 forearm fractures) who underwent intramedullary nail treatment due to radius and ulna fractures were retrospectively analyzed. Adult patients with displaced forearm double fractures were included in this study. Patients with open physeal lines, pathological fractures, Monteggia and Galeazzi fractures, distal radioulnar joint instability, bilateral fractures and bone loss were excluded.ResultsThirteen patients were male (72.2 %) and five were female (27.8 %). Average age of the patients was 35.16 (18–63). Twelve patients (66.7 %) suffered right and six patients (33.3 %) left forearm fractures. Average follow-up period was 77.7 (55–162) weeks, average bleeding amount was 51.11 (15–100) ml, average time to bone union was 11.3 (8–20) weeks, average surgery time was 61.94 (45–80) min and average fluoroscopy time was approximately 2 (1–5) min. According to Grace-Eversman criteria, results were excellent in 14 (77.8 %) patients, good in 3 (16.8 %) and acceptable in 1 (5.6 %). Average DASH questionnaire score was 15.15 (4–38.8). There was no iatrogenic vascular, neural and bone injury during surgery. There was late rupture of extensor pollicis longus tendon in one patient, 4 months after surgery.ConclusionIntramedullary fixation method has advantages, such as closed application, short surgery period, good cosmetic results and early return to movement. We think intramedullary fixation method may be used as an alternative treatment method to plate osteosynthesis in surgical treatment of radius and ulna diaphyseal fractures.