Inclusion Criteria:  directly or indirectly (through a respondent) will have expressed their will to participate in the study by signing and dating the informed consent; will have reached the age of 65 at the time of signing the informed consent; he/she will have been diagnosed with a fracture in the pertrochanteric, intertrochanteric or subtrochanteric region of the femur, stable or unstable, not previously treated; based on the investigator's judgment, he will have a regular indication for surgical treatment with an intramedullary nail; the fracture will be treated with the Chimaera short nail (length = 180 mm) and one or two telescopic lag screws, according to the manufacturer's instructions for use.  Exclusion Criteria:  will undergo surgery to treat the results of a previously treated fracture; he/she will have been diagnosed with a pathological fracture of oncological origin (primary tumor or skeletal metastasis); he/she will have been diagnosed with a fracture in the diaphyseal and/or distal region of the femur; he/she will have been diagnosed with an open fracture (type II and III according to the classification of Gustilo and Anderson) of the proximal femur; he/she will have been diagnosed with multiple fractures (including bilateral proximal femur fractures); in the pre-or intra-operative phase it will be decided to treat the fracture with the long version of the Chimaera nail and/or with non-telescopic cephalic screws (fixed length); will have a medical condition that constitutes a contraindication to treatment with Chimaera according to the manufacturer's instructions for use; will have a suspected or certified hypersensitivity/allergy to some component of the device that comes into contact with the patient; will present some clinical condition that, in the Investigator's opinion, could interfere with the procedures of the Clinical Investigation or that could jeopardize the safety of the patient; at the same time he will be treated with an unauthorized device that cannot be removed without endangering the safety of the patient; will be participating in other clinical trials or had participated in other clinical trials in the 3 months before signing the informed consent.