The term “bone marrow edema” often appears in hospital tests or diagnostic results, and some clinicians are not quite sure what it means or how serious the disease is, and of course, patients or their families are not sure what it means. How can bone marrow edema be detected? Bone marrow edema is a sign of bone matrix edema, fibrous tissue hyperplasia and inflammatory cell infiltration as the main pathological manifestations. With the development of technology and the widespread use of MRI, the sign of bone marrow edema has gradually been recognized, but it has not attracted widespread attention until recent years, when some scholars have reported relevant studies. The causative factors of bone marrow edema are still uncertain, including: trauma, hormones, and mechanical stress alterations. Biomechanical alterations are one of the causes of bone marrow edema, and mechanical stress may play an important role in the development of bone marrow edema. Mechanical stress alterations lead to trabecular fractures in the weight-bearing area and the development of bone marrow edema. MRI is currently the best means of diagnosing and evaluating bone marrow edema. The degree of pain is consistent with the severity of bone marrow edema, and as the severity of bone marrow edema decreases on MRI, the patient’s pain decreases accordingly, specifically in this case, the patella, which is caused by increased stress on the patella due to excessive repetitive knee flexion activities. Myeloid edema syndrome usually occurs in the hip joint. The term “bone marrow edema” emerged with the use of magnetic resonance imaging (MRI), which means that only MRI examinations can detect the presence of bone marrow edema at a relatively early stage, because MRI examinations are sensitive to water and the bone marrow edema shown is more characteristic, so the diagnosis can be made directly. That is, the bone marrow edema area is white on the T2WI compression lipid image of MRI and black on T1WI. Other imaging tests are not able to detect or diagnose bone marrow edema (including X-rays, CT, PET-CT, ultrasound, etc.).