Avascular osteonecrosis, simply known as Osteonecrosis is a condition in which the bone tissues die, as a result of a stoppage or impairment in the blood supply. This disease doesn’t present with any signs and symptoms initially, however, patients begin to present with complains gradually. This condition can deteriorate to bone collapse if not well managed. This disease mostly happens at the hip, although it also occurs in other parts of the body such as the shoulders, knees, ankles and so on. There are some factors that predispose people to develop osteonecrosis. Some of the conditions include fractures of bone, joint dislocations, excessive consumption of alcohol, frequent use of steroid drugs and so on. There are also cases where this disease just happens, even without the presence of any predisposing factor. Physicians do diagnose this disease at first, taking the medical and personal history of the patient. If the doctor notices that there might be a chance the patient has osteonecrosis, further evaluations are done. Some of the evaluations include medical imaging. This includes X-ray, CT SCAN, MRI and so on. The bone biopsy might be done in rare cases. The good news is that this disease can be treated successfully if diagnosed on time. Some of the treatment procedures include medications, physiotherapy, and surgery. Patients are encouraged to stretch often but are told not to walk in the affected limb. Surgical procedures may involve processes such as decompression, osteotomy, bone grafts, or replacement of the joint. According to statistics, it has been noted that females are more affected than males. Doctors will start using autologous bone marrow stem cells for the treatment. Exosomes have also become a way of managing this disease.
Symptoms Of Avascular Osteonecrosis
Patients affected by osteonecrosis usually presents with no symptoms initially, however, the signs and symptoms might start presenting gradually. The bone might collapse if the disease is left untreated for a long time. In addition, the duration between the initial symptoms and the collapse of the bone differs. This could range from some few months to more than a year. Any bone of the body can be affected, however, the disease mostly affect parts of the body such as the shoulder, knee and the hip. The majority of the cases do affect multiple parts of the body at the same time. Although the most commonly affected part of the body is the end of the femur (the thigh bone). The signs and symptoms that could develop include:
- Pain – Patients do experience pain as the disease progresses. Patients might not feel the pain initially until some pressure is exerted on the affected bone, usually the hip or thigh bone. Subsequently, the pain would become more intense and obvious, even without having to put any pressure on the affected part.
- Walking difficulties – As the disease progresses, patients could develop a limp as a coping mechanism for the pain and sometimes this persists after medical treatment and requires physiotherapy to gain a normal gait again.
- The stiffness of Joints – This could occur as a coping mechanism as well. Some people completely avoid the use of the affected joint and as a result, the joint could become stiff. This can also be treated with physiotherapy.
Causes Of Avascular Osteonecrosis
Avascular necrosis affects people between the ages of 20 and 50. Osteonecrosis is predominantly secondary to an already existing disease. Below are some of the causes of avascular necrosis;
- Abuse of corticosteroids: The prolonged use of corticosteroids, especially in the treatment of chronic diseases have been linked with the development of avascular necrosis. It has been suggested that corticosteroids do affect the way the body metabolizes fatty foods. These fatty materials tend to deposit and accumulate in the blood vessels, which makes them narrower, therefore reducing the amount of blood that eventually gets to the bone.
- Trauma, Dislocation or Fracture of the Bone: Osteonecrosis occurs as a result of a bone fracture or a bone deformity. These bone injuries can cut off or interrupt the blood supply to the bones, which would lead to ischemia of the bones, and subsequently bone necrosis.
- Excessive consumption of alcohol: Excessive consumption of alcohol also tends to cause the build-up of fatty materials in the blood vessels. This eventually constricts the vessels, decreasing the amount of blood that gets to the bones.
- Other diseases: There are some other diseases that are associated with the interruption of blood supply to the bones. Some of them include the following
- Autoimmune diseases: These are diseases in which the immune system of the body fails to recognize the body tissues. This leads the immune system to attack the tissues, causing different degrees of injuries and damage. Some of these diseases might lead to the interruption of the supply of blood to the bones.
- Gaucher’s disease: This is a metabolic disease that causes the accumulation of fatty substances in the organs. This disease is usually passed down from parents to their offspring.
- Sickle cell disease: This is blood disorder in which patients do have an abnormal hemoglobin.
- Medications: There are some drugs that predispose patients to osteonecrosis. Examples of these drugs are the ones used in the treatment of cancer. This includes radiation and chemotherapy drugs
- HIV infection
- Inflammation of the pancreas.
How do Doctors diagnose Osteonecrosis?
Physicians do diagnose this disease at first, taking the medical and personal history of the patient. If the doctor notices that there might be a chance the patient has osteonecrosis, further evaluations are done. Some of the evaluations include medical imaging. This includes X-ray, CT SCAN, MRI and so on. A bone biopsy might be done in rare cases. The X-ray of the disease usually appears normal initially, however, it looks more radio-opaque. Patients will present with a radiolucent area, as a result of the collapse of the subchondral bone. This is because of the saponification, and calcification of the fat materials in the bone marrow.
Treatment of Avascular Osteonecrosis
There are different methods used in the treatment of avascular necrosis. The most commonly used treatment method is a total hip replacement. However, a total hip replacement has some downsides. Some of them include long recovery periods and short life spans of the joint. Another method used in the treatment of avascular necrosis is core decompression. This is a method where the internal bone pressure is reduced by making a hole in the bone. A living bone chip and an electrical device that can induce new growth of vessels are implanted in the bone. The progression of the disease can be interrupted by transplanting nucleated cells from bone marrow into avascular necrosis lesions after core decompression.
The use of Stem Cell Therapy in the treatment of Osteonecrosis
Scientists are working on ways to start using autologous bone marrow stem cells for the treatment of osteonecrosis. This procedure involves a minimally invasive decompression procedure. This treatment is suitable for patients at the early stage of avascular necrosis.
References
Brambilla, L., Esposito, L., Nazzaro, G. and Tourlaki, A. (2017). The onset of Osteonecrosis and Merkel cell carcinoma during low-dose steroid therapy for rheumatic polymyalgia. Clinical and Experimental Dermatology, 42(6), pp.702-704.
Corticosteroid therapy still the mainstay for polymyalgia rheumatica and giant cell arteritis. (1998). Drugs & Therapy Perspectives, 12(5), pp.8-10.
Evans, J. and Hunder, G. (2000). POLYMYALGIA RHEUMATICA AND GIANT CELL ARTERITIS. Rheumatic Disease Clinics of North America, 26(3), pp.493-515.
Perfetto, F. (2005). The seasonal pattern in the onset of polymyalgia rheumatica. Annals of the Rheumatic Diseases, 64(11), pp.1662-1663
Get More Stem Cell Information at iSTEMCELL
