Avascular necrosis

Avascular necrosis (osteonecrosis or bone infarction) is the necrosis of bone tissue due to blockage of blood supply. Hematopoietic cells are the most sensitive to low oxygen levels and are the first to die after a decrease in blood flow (usually within 12 hours). This triggers the process of bone marrow death and subsequent destruction of the entire bone.

Avascular necrosis of the femoral head is most common. Basically, the hip joint suffers from a combination of unreliable blood supply and high stress in this area while standing.

Symptoms and causes of avascular necrosis of the femoral head

At the initial stage of the disease, symptoms do not appear. Joint pain may gradually develop, limiting the ability to move. With a complication, there is a risk of bone or nearby joint surface destruction.

The main risk factors are bone fractures, hip dislocation, alcoholism, and high-dose steroid use. Sometimes avascular necrosis can develop as a side effect of radiation therapy, chemotherapy, or organ transplantation. Osteonecrosis is also associated with diseases such as cancer, lupus, sickle cell anemia, HIV infections, Gaucher disease, and caisson disease.

Examination for avascular necrosis of the femoral head

In the early stages of avascular bone necrosis, bone scintigraphy and MRI are the preferred diagnostic methods. X-rays at this stage of the disease often do not show any abnormalities. In the later stages, the image looks less transparent than usual.

Treatment of avascular necrosis of the femoral head

Various methods are used to treat avascular necrosis of the femoral head. The most common approach is a complete hip replacement.

Endoprosthetics for avascular necrosis of the femoral head is an effective method for the elderly. When installing a prosthesis, young patients may eventually need to undergo repeated surgery due to the expiration date.

Other treatments include bisphosphonates. These are medications that reduce the rate of bone destruction. Decompression (tunneling) of the core of the affected hip bone is sometimes performed. The internal pressure of the bone is relieved by drilling a hole in it and implanting living bone tissue and an electrical device to stimulate new vascular growth.

Also, with avascular necrosis, a microvascular free fibula graft can be installed. As part of this procedure, part of the fibula, along with its blood supply, is removed and transplanted into the femoral head. After surgery, physical therapy is usually prescribed.

The progression of the disease can be stopped by transplanting immature hematopoietic cells from the bone marrow into the affected area of the bone during decompression. However, this procedure is currently being carried out only as part of clinical trials.