If there is still a gap in the medial gap of the knee on the X-ray uploaded by the patient (even if it is a very narrow 2-3mm gap), whether to perform joint replacement surgery, or arthroscopic surgery depends on the change in the joint gap on the X-ray of the outpatient single-leg weight-bearing orthopantomograph; if the medial gap disappears on the single-leg weight-bearing orthopantomograph, joint replacement will be performed; conversely, if the medial gap is the same on the single-leg weight-bearing orthopantomograph and the seated or tripped film, plus there is meniscal damage on the MRI (magnetic resonance imaging), minimally invasive arthroscopic surgery may be sufficient.