The patchy slightly high signal shadow seen in the left distal femur and proximal tibia is an MRI finding, which indicates that there may be localized bone infectious lesions, bone contusion, osteoarthritis, and so on. 1. Infectious bone lesions: such as osteomyelitis or tuberculosis, usually accompanied by fever, chills, elevated white blood cells and C-reactive protein. 2. Bone contusion: It can also cause bone marrow edema with symptoms of joint pain, swelling, and limitation of movement with a clear history of trauma. 3. Osteoarthritis: Narrowing of the joint space, wear and tear of the cartilage, and increased stress between the bones can cause chronic bone marrow edema. A patchy slightly high signal shadow of the left distal femur and proximal tibia is present. Nuclear magnetic examination found that the left distal femur and proximal tibia patchy slightly high signal shadow, should promptly consult a doctor for diagnosis and treatment, clear diagnosis, and then follow the doctor’s instructions for targeted treatment, so as not to delay the condition.