To evaluate the efficacy and safety of internal fixation or arthroplasty for hip fracture patients over 75 years of age with multiple medical complications through the operation time, intraoperative bleeding, time to start weight bearing activities and other indicators.

Patients will be enrolled from five study centers, each center will be free with regard to surgical indications and postoperative prescription. The unstable fractures were A2 and A3 (31 A2.2 and 3, and 31 A3.3) according to the AO classification. The investigators will use a prospective randomized approach to determine the treatment procedure for patients. The patients undergoing arthroplasty will be regarded as the experimental group and the patients who accept the intramedullary nail fixation will be regarded as the positive control group. All patients will receive consistent anticoagulant, analgesic and other therapeutic measures in the perioperative period except for the different surgical methods. The two groups will be compared in age, sex, pre-fracture place of residence, fracture type and preoperative comorbidity. The investigators will evaluate the effect and safety of the two types of operations by comparing the surgical related data, complication incidence and functional rehabilitation.

Inclusion Criteria:

• Intertrochanteric fractures of the femur need surgery
• Male and female, age more than 75 years old
• Combined with more than one medical complication, including hypertension, cerebral infarction, respiratory failure, renal insufficiency, coronary heart disease, diabetes, heart failure, pulmonary infection, heart rate, water and electrolyte disorders
• The patient is still able to tolerate surgery through the anaesthesia and related department assessment
• Signed written informed consent

Exclusion Criteria:

• No complications associated with internal medicine
• Mild fracture displacement and conservative treatment required
• Multiple trauma involving more than one organ system
• Known to have progressive malignant neoplasms
• It is not possible for the subjects to follow the test scheme, such as uncooperative attitudes, inability to return to the research centre for follow-up visits and inability to complete the study