What is femoral head avascular necrosis?
Femoral head necrosis also is known as ONFH (Osteonecrosis of the Femoral Head) or avascular necrosis of the hip in medicine. The femoral head is due to a variety of causes of poor local blood supply of the femoral head and it causes bone cells further ischemia, necrosis, bone fracture, a lesion of femoral head collapse. The first definition of this disease for the first time since 1888 to now, femoral head avascular necrosis has been made from a rare disease to common bone diseases. Especially since hormone has wide application, the disease incidence increased gradually. According to incomplete statistics, there is 30 million femoral head avascular necrosis patient at present in the world. Femoral head necrosis occurred without significant gender differences, any age of people could get it. But there is a marked increase in the patients with hormone using history, alcohol abuse, hip trauma history.
This bone disease occurs at any age but with 31-60 years old most, no gender differences. This disease first manifested as hip or joint pain, dull pain, especially obvious after activity. It can lead to the further development of the hip joint dysfunction. Femoral head avascular necrosis can seriously affect the quality of life and the ability to work, if not treated promptly, it can lead to lifelong disability in the patient.
Femoral head avascular necrosis classification
First presenting symptom is a body pain and bone pain, especially around the hip joint, interior and posterior side of thigh or knee. The pain is a dull pain, intermittent pain at the beginning, it can relief when patient get rest. But some patients pain is consistent even they get to rest in bed. although there are no obvious morphological abnormalities on X-ray of the hip bone and joint, the hip has limited function in different degrees. In the late stages, the femoral head collapses and breaks and becomes deformed. Some can cause subluxation of the hip. In sum, early stage presents mainly is the pain, late-stage presents mainly are hip dysfunction with pain.
Avascular necrosis of the hip bone classification
Femoral head necrosis classification
There are four stages of femoral head avascular necrosis.
- Ultrastructure variation stage (stage I)
- Sensation stage (stage II)
- Necrotic stage (stage III)
- Disability stage (stage IV)
Ultrastructure variation stage (stage I)
X-ray showed trabecular bone structure that is the heavy bearing system is disarranged, fractured, femoral bone head get roughed. The clinical manifestation is a slight pain with movement.
Sensation stage (stage II)
X-ray showed a cystic lesion in femoral head bone and uneven density around the cystic lesion. Trabecular structure disarranged, shown fuzzy or collapsed. Pain or movement limitation appear when collapse area is more than 10-30%.
Necrotic stage (stage III)
We will see obvious morphologic changes on x-ray. The femoral head can appear the edge is not complete, vermiculata shape or flat shape. Part of the trabecular bone structure disappear, uneven bone density, acetabulum, and the femoral head gap widened or narrowed. Osteophyte appears in some cases. The clinical manifestations are severe pain, intermittent claudication, limb joint activity limitation, have different degrees of reduction.
Disability stage (stage IV)
The structure of the femoral head changed obviously, there is a large area of collapse or flat and irregular trabecular structure variation. The acetabulum and femoral head gap are disappeared. The clinical manifestations include pain, dysfunction, stiffness, inability to walk, dislocation or subluxation, and limited functional activity of the knee.
Eventually, most patients present joint deformity and secondary osteoarthritis. Although there are numerous treatments methods in the clinic, the effect of treatment is not very satisfactory. But one key point has been proved that the earlier the treatment proceeds, the better the effect can get.
We will introduce femoral head avascular necrosis diagnosis and femoral head avascular necrosis treatment methods in detail in our other articles.