Objectively speaking, the treatment of femoral head necrosis, especially the preservation of one’s own hip joint after collapse (referred to as “hip preservation”), remains one of the most challenging tasks in orthopaedics, not only in China but also in other countries around the world. The success rate of all available treatments, if applied indiscriminately, does not exceed 50%. Therefore, the real expert in femoral head necrosis is not the one who has mastered any magical method, but the one who knows first of all how to choose, which patients can be treated without treatment, which patients can be treated non-operatively, which patients must be operated as soon as possible; which patients can be treated with minimally invasive surgery, which patients need to be treated with repair and reconstruction of exposed joints; which patients can be deferred for joint replacement, which patients’ joints are not The second thing is to know how to choose the right one. Secondly, on the basis of knowing the choice, we master the full set of treatment techniques from non-surgical, to minimally invasive surgery, to traditional repair and reconstruction surgery, to artificial joint replacement (from initial to revision). Unfortunately in China, there are too few such doctors, and they are far from meeting the clinical needs. To return to the question of whether it is better to “replace the joint” or “preserve the joint” after the collapse of femoral head necrosis, the first thing is to have a correct understanding of the collapse. The degree, extent, and site of collapse are important, but the time of collapse, the current and future trends of its effects on the patient (symptoms, hip mobility, joint stability, etc.) are also important, if not more important, but it is precisely the latter that has not been given enough attention. Conclusion: The clearer the understanding of the collapse and the more accurate the judgment of the collapse trend, the more reliable the choice of “joint replacement” or “joint preservation” will be, otherwise, there will be either a missed opportunity, or over-medication, or wrong treatment. In either case, it is very regrettable and frustrating.