Introduction: Fragility fractures around the proximal end of the femoral bone have been increasing the last years, increasing the pressure at the national health care systems and the hospital expenses. Peri-trochanteric fractures have been treated successfully with anatomic intramedullary nails of the proximal femur, giving a stable fixation in order to allow early mobilisation of these frail patients. Some of these nail allow a second (anti-rotational) screw through the nail in the femoral head. In the present study the use of this additional screw is studied, in terms of quality of reduction, mobilization and complications. Materials & methods All patients who were treated in the same hospital for peri-trochanteric fracture between January 2017 and December 2019 were included in the study. The patients were randomly assigned into group A, were the treatment included intramedullary nailing using one femoral hip screw, and group B, were the treatment included a second anti-rotational screw as well. The patients were followed up clinically and radiologically, for at least 3 months post-operatively. Demographic and operation data were collected alongside with radiographic and complication data. Results A total of 118 patients aged 82.7 years were included in the study after exclusions. There were no statistically significant differences between the two groups regarding the ASA grade, Nottingham Hip fracture score, Koval score, Mental score, operation time, transfusion and operative radiation dose and time (p > 0.05). In group A more complications were observed (p < 0.05). The radiological measurements were statistically significant different. CART analysis revealed that the use of a single screw in the femoral head for the subgroup of the unstable peri-trochanteric fractures (Jensen Type 4–5 – AO31A2.2 and above), has the tendency of developing more post-operative complications. Conclusion The use of an additional anti-rotational screw for the unstable peri-trochanteric fractures (Jensen Type 4–5 and AO 31A2.2 and above) could prevent complications such as varus collapse and cut-out.