Objective: To assess the clinical, radiological and functional evolution of osteosynthesis using a cephalomedullary nail, in unstable trochanteric fractures of the femur, over a one-year postoperative follow-up. Methods: Fourteen men and 23 women of mean age 77.7 years were evaluated. Twenty-seven of them had fractures classified as AO/ASIF 31A2 and ten as 31A3. The patients were evaluated clinically, radiologically and functionally one week, two weeks, one month, two months, six months and one year after the operation. Results: The clinical complications comprised five cases of death, one case of calcaneal ulcer, one case of acute arterial obstruction and two cases of deep vein thrombosis. The radiographic evaluation showed that the mean cervicodiaphyseal angle in the immediate postoperative period was 132.5°. The mean tip-apex index was 22.8 mm. After one year,