Necrosis of the femoral head

Necrosis of the femoral head

Necrosis of the femoral head is a disease that results from the death of the femoral head due to a lack of blood supply to the femoral head (also known as avascular necrosis or femoral head ischemia or femoral head necrosis). When the blood supply to the femoral head is lost or decreased, this results in bone death and leads to the deterioration and collapse of the bone's structural shape. This lack of blood supply may be due to many known and some unknown causes, and it may occur at all ages, but it is most common between the ages of 30 and 60 years.

Causes and Symptoms

Necrosis of the femoral head may occur for known reasons such as:

Injury or fracture of the femoral head: Injuries, fractures or dislocations in the hip joint may cause damage to the blood vessels that supply the femoral head. In some cases of cancer treatment that include radiation therapy, as radiation may cause bone weakness and damage to the blood vessels that supply the bone.

Fatty deposits in blood vessels: Fat deposits in blood vessels may obstruct blood flow to the microcirculation, leading to decreased blood flow.

Some systemic and immune diseases: Some diseases such as hemophilia, sickle cell anemia, or Gaucher's disease, which cause decreased blood flow to the bone.

Steroid use: High and excessive doses of steroids may cause femoral head osteonecrosis. Although the exact cause is unknown, some scientific studies suggest that taking excessive doses of steroids leads to increased accumulation of lipids in the blood vessels, leading to decreased blood flow to the femoral head.

Alcohol: Excessive alcohol consumption leads to the deposition of fats in the blood vessels, leading to decreased blood flow to the femoral head.

There are other unknown causes that represent about 25% of femoral head osteonecrosis cases, in which the cause of decreased blood flow to the bone is unknown.

Many patients may not experience any symptoms in early cases. When the condition begins to worsen, the patient may only experience pain when exerting effort or putting some weight on the affected joint. When the condition is advanced, the patient may experience continuous pain even when resting. The pain is usually concentrated in the upper thigh area, the side of the hip and the buttocks, and many cases occur in a lack of ischemia on both sides (i.e. in the hip joints). When the patient develops femoral head necrosis, this leads to roughness in the hip joint as a secondary disease resulting from the rupture and death of the femoral head bone.

Diagnosis

Clinical examination: The doctor usually examines the joint by pressing on it in multiple areas on the sides of the joint to see if there is pain in the joint, and by moving the joint in different directions to see if there is pain or limitation in movement.

X-rays: Show the extent of the change in the structural shape of the joint and whether there is roughness of the hip joint associated with the disease, but they do not show the condition in the early stages.

MRI: Shows in detail the changes that occur in the bone even in the early stages, which may indicate a lack of blood supply to the head of the femur.

Radioisotope bone imaging: The patient is injected intravenously with a small amount of harmless radioactive isotopes, which are followed up via imaging to identify the damaged and healthy parts of the bone.

Femoral head necrosis is diagnosed in four stages:

Stage 1: The patient usually has no complaints or has mild pain. However, as the condition worsens, the pain begins to increase, especially when standing and walking. X-rays appear normal at this stage. Magnetic resonance imaging is used to show the location and size of the part that lacks blood flow. The patient may also need to have radioisotope bone imaging to confirm the diagnosis.

Stage 2: X-rays show changes in the tissue of the femoral head, but the head of the bone is completely round and has not lost its structural shape.

Stage 3: There is flattening of the femoral head, but without roughness (cartilage erosion) in the hip joint.

Stage 4: There is a change in the structural shape of the femoral head and roughness in the hip joint.

Femoral head necrosis

Treatment

Conservative non-surgical methods: The intended goal is to alleviate and curb the worsening of the condition and bone death, and are usually resorted to in early cases, and these methods include: non-steroidal anti-inflammatory drugs, osteoporosis medications, blood thinners, rest and weight loss, and physical therapy. Because most patients do not suffer from any clinical symptoms until the condition develops, other methods may be used for treatment other than these conservative methods.

Surgical methods: Depending on the degree of bone necrosis and the patient's condition, one of the following procedures may be performed:

Perforation of the femoral head: This is done for the case in which there has been no complete change in the structural shape of the hip joint, and it is done through a small hole in which the surgeon removes the damaged part of the bone, thus stimulating the bone to build new blood vessels and new bone cells.

Bone grafting: This is done by taking a part of a healthy bone and implanting it in place of the damaged part of the femoral head, in order to strengthen the bone in the damaged area and stimulate the construction of new bone cells and blood vessels.

Hip joint replacement: When there is severe wear and tear in the joint and loss of the structural shape of the joint, or when other treatment methods fail, a complete hip joint replacement is performed, which eliminates the disease completely in this way and eliminates pain and restores movement. Regenerative therapy: It is a modern method for dealing with some cases of femoral head necrosis, by extracting bone marrow from the patient and purifying it, then injecting it into the damaged part of the femoral head. The bone marrow contains stem cells and other regenerative cells with bone cells that work to stimulate the building of blood vessels and cells