[Medical Q&A] If you suspect femoral head necrosis, what tests should you do?

Planner: Chinese Medical Association

Reviewer: Wang Jian, Chief Physician, Nanfang Hospital, Southern Medical University

If femoral head necrosis is suspected, two tests are needed: X-ray and magnetic resonance imaging (MRI).

X-ray examination is one of the most popular examination methods in orthopedics, and it is inexpensive. X-rays can show the shape of the femoral head. Once signs of femoral head necrosis appear, it indicates that the disease has developed to the middle or late stages. Although X-ray examinations cannot detect femoral head necrosis in the early stages, they can assist doctors in preliminarily determining the location of the lesion (lumbar spine, knee joint and femoral head). X-ray examinations can determine the severity of femoral head necrosis and are a good tool for evaluating the staging of femoral head necrosis.

MRI is a highly sensitive method for diagnosing early-stage femoral head necrosis. Even if the femoral head has not changed in shape, MRI can be used to observe whether the femoral head bone and soft tissue show signs of necrosis. In the early stages of femoral head necrosis, MRI can show changes in the bone marrow. At this time, X-rays cannot show abnormalities.

CT is not recommended for patients with femoral head necrosis because of its poor soft tissue imaging and low sensitivity. Of course, CT or radionuclide imaging may be performed to differentiate other diseases or when the diagnosis is unclear.