How to observe the degree of femoral head necrosis under X-ray?

The process of femoral head necrosis can be roughly imagined as a process in which apples are eaten by moths: at first, moths are not seen at the beginning, until the pulp under the peel is slowly eaten, and then most of the pulp deteriorates, and the whole apple rots and deforms.

X-ray examination has its limitations. For early necrosis, it is difficult to judge, and MRI is needed. X-ray can show necrosis of femoral head, often in late stage. However, for patients with femoral head necrosis, pelvic radiography is still the first choice for auxiliary examination because of its low price.

Femoral head necrosis, as a progressive disease caused by local blood circulation disorder of femoral head, has specific manifestations on pelvic X-ray films, which can provide important clues for the diagnosis and staging of the disease and guide further examination and treatment. Today, I will briefly introduce how to judge the degree of femoral head necrosis according to X-rays.

Internationally, femoral head necrosis is usually divided into five stages:

Stage I: at the early stage of femoral head necrosis, X-ray films have no specific manifestations, which need to be diagnosed by combining medical history, magnetic resonance imaging and pathological examination.

Phase Ⅱ: X-ray showed slight changes in subchondral bone of femoral head: partial necrosis, absorption and cystic change; Part of it is hyperosteogeny and sclerotic reconstruction.

Stage ⅲ: The subchondral bone changes of femoral head developed further, and the typical "crescent sign" can be seen on X-ray film, that is, there is a semi-moon translucent area in the cartilage area.

Stage Ⅳ: Femoral head collapse deformity with arthritis: the gap between femoral head and acetabulum is narrowed, and bone hyperplasia at the acetabulum edge.

Stage ⅴ: The deformation of femoral head is more serious, the manifestations of osteoarthritis are more obvious, the joint space disappears, and the femoral head is not in the acetabulum.

The depth of femoral head necrosis determines the treatment of femoral head necrosis. Early necrosis of femoral head can be relieved by anti-inflammation and painkillers, or the progress of the disease can be controlled by decompression of medullary cavity, so as to achieve the purpose of preserving hip joint.

In the late stage of the disease, artificial joint replacement is needed to restore the function of hip joint.