Stem Cell Therapy for Avascular Necrosis of the Hip

Stem cells have properties of self-renewal and the ability to differentiate into different cell types. The stem cells are the repairing cells of the body present mainly in the hollow of the bones in adults. The spongy tissue known as the bone marrow is aspirated to harvest stem cells in adults. The stem cell therapy also known as regenerative medicine has been used recently in a number of diseases including avascular necrosis.

The avascular necrosis (osteonecrosis) of the head of the femur results from disruption or impedance of the blood flow to the bone. The bones in our body are living tissues that require blood supply for their healthy function. The bones have a constant turnover which is dependent on intact blood supply.

Avascular Necrosis of the head of the femur.

The disruption of the blood supply of the head of the femur may result from a direct injury such as fractures, dislocations, or surgeries around the hip. The nontraumatic causes include corticosteroid abuse or long term alcohol intake. Certain medical conditions resulting in excess of clotting cells/factors may also lead to osteonecrosis of the head of the femur.

The disruption of blood supply leads to a cascade of events causing bone death. The body tries to revascularize the dead bone and lays down new bone. The process is impeded by decreased blood flow and increased pressure inside the head of the femur. The dead bone ultimately results in the collapse of the spherical surface of the head.

The collapsed head results in the loss of spherical contour. This results in attrition causing arthritic changes in the head of the femur and the cup of the acetabulum. The patient experience debilitating hip pain and loss of movements about the hip joint. The day to day activities of the patients may be severely affected.

A greater number of affected patients happen to be in an active age group and may require joint replacement in advanced stages. Regenerative therapy has a role to play in the early stages of avascular necrosis of the hip i.e before the collapse of the spherical surface.

The early stages of avascular necrosis are usually diagnosed on an MRI or a bone scan. There are usually no X-ray findings in the early stages of osteonecrosis. The stem cells have an ability to change into bone cells and repair the damage caused by the dead bone. The repaired area is revascularized by stem cells forming blood vessels.

There are mainly two types of stem cells, embryonic stem cells, and adult stem cells. The adult stem cells may be harvested from the bone marrow, fat cells, or the blood. The embryonic stem cells are harvested from human embryos restricting their use due to ethical considerations.

The bone marrow-derived stem cells are commonly used in the treatment for early stages of avascular necrosis of the hip joint. After appropriate anesthesia, the bone marrow is aspirated from a part of the pelvic bone known as the iliac crest. The marrow aspirate is then spun in a specialized machine to get a concentrate of stem cells.

The concentrated stem cells are then injected in the area of the necrosed bone under intraoperative X-ray guidance. The stem cells are also used in conjecture with other joint preservation techniques such as core decompression of the head of the femur.

The patients are usually able to go home the same day of the procedure. They are advised partial weight-bearing for 4-6 weeks when performed along with core decompression. The patients are also advised to avoid high impact activities. They are followed every 6 months to monitor the progression of the avascular necrosis.

Stem cell therapies have shown significant benefits in the regeneration of the avascular area of the bone. Unfortunately, avascular necrosis progresses in a number of patients to advanced stages.

In advanced stages, a total hip replacement provides excellent relief from pain and the patients are quickly able to get back to the activities they enjoy. The joint replacement surgery has revolutionized the treatment of advanced cases of avascular necrosis of the head of the femur.

Read more about Avascular Necrosis of the Hip Joint here.