Three years ago, 53-year-old Ms. Yin had a right femoral neck fracture caused by a car accident and underwent a right artificial total hip replacement in a local hospital. Unexpectedly, six months after the surgery, she started to feel pain in her right hip when walking, without any fever and no local redness or swelling. At that time, she thought it was a normal post-operative pain and did not treat it. However, the pain gradually increased and she went to the local hospital for follow-up. The doctor was unable to give a reasonable explanation after the routine examination, and when she saw that the pain was affecting her daily life, he suggested a revision surgery. Ms. Yin thought that the pain could not happen for no reason and that the cause had to be clearly identified for symptomatic treatment. So, she consulted many doctors, but several major hospitals gave results that were either unexplained or suspected to be loose. Later, after being introduced by a friend, Ms. Yin came to the orthopedic department of Shanghai Ninth People’s Hospital. Although the results of the routine examination were the same as those of other hospitals, she underwent another examination of “FSA (Fluoroscopic Stereophotogrammetric Analysis)”, in which she clearly saw the movement of her In the results of the examination, she clearly saw the movement of her joint prosthesis in the body and the report also gave an indication of millimetric loosening of the femoral stem prosthesis. Later, she underwent surgery, and the surgeon confirmed intraoperatively that there was indeed loosening between the femoral stem prosthesis and the femur, and that the joint stem could be easily pulled out, which was the cause of Ms. Yin’s right hip pain when walking after surgery. X-ray of the patient’s affected area With the aging of our population and the occurrence of accidents such as car accidents, the number of artificial joint replacement cases is gradually increasing. These surgeries effectively repair the trauma of patients and allow them to resume a normal life. However, the ensuing complications are also increasingly appearing in clinical practice. The aseptic loosening of the joint mentioned above is a typical case. Since the prosthesis is in the human body and its tissue structure is very different from other tissues in the human body, a small loosening like the one above is difficult to detect by common clinical imaging methods such as X-rays and CT. This poses a great problem for patients and doctors. With the development of science and technology, new methods of observing the in-body movement of the prosthesis have emerged. One of them is “dynamic stereoscopic measurement”. The key to its success in this case lies in the words “dynamic” and “stereoscopic”. “Dynamic” means that the doctor can see the movement of a joint, unlike static images like X-ray or CT; “stereoscopic” means that the doctor sees the bones and prosthesis in three dimensions, unlike projections like X-ray or CT. tomography. So what exactly does the doctor see through “dynamic stereoscopic measurement”? To use an analogy, it is as if we have a fluoroscopic eye, during the patient’s movement, we can follow through the muscle skin and see the entire movement of his/her bones and prosthesis. The motion image is one aspect, and through the precise calculation of the computer system, we can also get the data of the spatial position of the prosthesis and the bone. In this way, the state of the prosthesis in the human body is clear at a glance, based on the ordinary 3D stereoscopic images, adding not only the information of the time dimension, but also the precise data of post-processing to speak. With this powerful helper, doctors can justifiably inform patients whether they are loose, impinged or infected after artificial joint replacement surgery, and patients can visualize the specifics. This provides an eye for analyzing the cause of failure after hip, knee and shoulder replacements, and planning for revision surgery. FSA detection process (shoulder joint examination) FSA analysis interface (knee joint examination) Motion process established by FSA technology (hip joint examination)