Before joint free body surgery, it is necessary to carry out routine examination of all kinds of samples, electrocardiogram examination and MRI examination of the surgical joint site. 1. Routine examination: Routine examination includes routine blood test, biochemical examination, routine examination of fecal and urine samples, etc. Through this kind of examination, it can determine whether the patient has inflammation, urinary system disease, coagulation dysfunction and other basic diseases before the operation, and help to make a comprehensive judgment on the patient’s coagulation function, body function and basic metabolism. 2. Electrocardiogram: electrocardiogram or cardiac ultrasound is a necessary examination before general anesthesia surgery, can determine through preoperative screening to determine the presence of cardiovascular diseases or heartbeat disorders and other symptoms of the surgery, can help effectively avoid intraoperative risks or make drug adjustments during and after the operation. 3. Nuclear magnetic resonance (MRI): MRI examination of the joint surgery site can help observe whether there is inflammation, fluid or stones in the joint cavity, and make accurate judgment of the muscle and joint structure of the surgery site. MRI can also help to determine the location of the free body, which can help to formulate a surgical plan. It is necessary to complete all the necessary examinations before the surgery to ensure that the body is in a stable state, to avoid serious complications during the surgery, and to effectively reduce the risk of surgery.