Femoral neck fracture is a common type of fracture in the elderly. For those without significant displacement (Garden I, II), more hip-preserving treatment strategies are adopted. The classic parallel hollow screw internal fixation for hip-preserving treatment is based on the sliding compression theory, and a clinical debate has gradually emerged, that is, the positive triangle And the two different spatial distribution methods of hollow nails and inverted triangle, which one is better. In addition, the distribution of hollow nails in actual operations is difficult to achieve a standard triangular distribution, and the damage to the epiphyseal vessels in the femoral head caused by repeated drilling of the guide needle cannot always be ignored. The relationship between the distribution and injury of blood vessels in the femoral head and the spatial distribution of hollow screws on the prognosis of head necrosis of non-displaced femoral neck fractures in the elderly is worth studying. This topic is based on the three advantages of TianJi orthopedic robots used in the elderly femoral neck fracture hollow nail hip-saving surgery: 1.standardized triangular nail placement with strong repeatability; 2. precise nail placement to reduce the risk of screw penetration; 3. limited guide pins The number of drill holes is to rule out repeated drill holes that damage the blood vessels in the femoral head. The preoperative and postoperative vascular injury in the femoral head (enhanced MRI of the femoral head) was compared to assess the prognosis of patients, and to clarify the influence of the spatial distribution of hollow screws on the blood supply and prognosis of the femoral neck fracture in the elderly.

the investigators choose 60-80-year-old Garden I or II patients with initial fractures. Hollow nails are the first choice for treatment of these patients. However, the spatial arrangement of hollow nails, local blood supply, and biomechanical properties have a greater impact on the prognosis of fractures. , There are still some controversies, which are also the current research hotspots. Our research conclusions may increase the success rate of hip preservation and will guide the treatment of these patients. This study is based on the precise placement of nails by the Dimensity orthopedic robot, and compares the vascular injury of the femoral head before and after the nail placement (femoral head enhanced MRI) to assess the prognosis of the patient. The influence of blood supply and prognosis of femoral neck fracture in the elderly.

Inclusion Criteria:

• A new initial intracapsular fracture of the femoral neck;
• Garden classification I or II;
• Accept closed reduction robot-assisted hollow nail surgery;
• ASA score 1-2, can tolerate anesthesia;
• Age 60-80 years old (inclusive);
• Able to fully understand and voluntarily sign informed consent.

Exclusion Criteria:

• Old or pathological fractures;
• Patients with acetabular fracture;
• Those who have general conditions or accompanying diseases that make it difficult for people to tolerate surgery, such as: coagulation dysfunction, or heart, liver, and kidney dysfunction;
• Severe infections systemically or locally;
• Those who refuse to sign informed consent;
• In any case, if the researcher believes that the patient is not suitable for this treatment or there are other factors that affect the efficacy of the observation of this study.