| The reduced blood flow to the bone may be the | | | | pain. As the bone progressively collapses, almost all |
| result of blockage by a blood clot, medication, or the | | | | patients develop pain aggravated by mechanical |
| deliberate stoppage of flow during surgery or | | | | stresses (eg, in the hip; standing, moving, walking) |
| because of measures taken to control a hemorrhage | | | | and eased by rest. Eventually, 67% of patients have |
| (major bleed). The most commonly affected sites | | | | pain at rest and 40% have pain at night, which may |
| are the proximal and distal femoral heads, the upper | | | | be accompanied by prolonged morning pain and |
| part of the leg bone that attaches into your hip. | | | | stiffness. |
| Other commonly affected sites include the ankle, | | | | Avascular necrosis begins as a painless bone |
| shoulder and elbow. | | | | abnormality. It can remain painless. The involved bone |
| Causes | | | | often later develops pain, especially with use. For |
| There are many causes of avascular necrosis such as | | | | example, if a hip joint develops avascular necrosis in |
| alcoholism, excessive steroid use, post trauma, | | | | the ball of the hip joint, pain can be noted - especially |
| caisson disease (decompression sickness), vascular | | | | with weight-bearing. As the ball of the hip joint |
| compression, hypertension, vasculitis, thrombosis, | | | | collapses from the degeneration of the bone from |
| damage from radiation, bisphosphonates (particularly | | | | aseptic necrosis, pain in the groin can be felt with hip |
| the mandible) and sickle cell anaemia. In some cases it | | | | rotation and pain can sometimes be noted with rest |
| is idiopathic (no cause is found). Rheumatoid arthritis | | | | after weight-bearing. |
| and lupus are also common causes of AVN. | | | | Treatment |
| Avascular necrosis is caused by impaired blood supply | | | | Although rest and the exercises can sometimes heal |
| to the bone, but it is not always clear what causes | | | | the affected portion of bone, surgery is usually |
| that impairment. Osteonecrosis often occurs in people | | | | needed. In as many as 80 percent of patients with |
| with certain risk factors (such as high-dose | | | | early disease, an operation called core decompression |
| corticosteroid use and excessive alcohol intake) and | | | | can spark regeneration of the bone. In this |
| medical conditions. However, it also affects people | | | | procedure, the surgeon drills out the damaged section |
| with no health problems and for no known reason. | | | | of bone up to the head of the femur. This opens up |
| Following are some potential causes of osteonecrosis | | | | channels for blood vessels to reach the diseased area |
| and other health conditions associated with its | | | | and foster the production of new bone. Hip pain is |
| development. | | | | relieved, and as many as 75 percent of patients |
| Symptoms | | | | avoid joint replacement later on. |
| In avascular necrosis of the hip, groin pain may | | | | Bisphosphonate medications, such as alendronate |
| extend down the front and inner portions of the | | | | (Fosamax), also may play a role in the treatment of |
| thigh or be felt in the buttocks. The person limps, | | | | this disease. In some studies of people with avascular |
| trying to minimize all hip movements. As the disorder | | | | necrosis affecting the ball portion of the hip joint |
| progresses, more and more tiny fractures of the hip | | | | (femoral head), bisphosphonates appeared to slow |
| occur, and the bone eventually collapses. The pain | | | | the progression of the disease and reduce pain. More |
| also increases, and the hip joint feels stiff and loses | | | | research is needed before doctors can make a |
| some of its range of motion. | | | | strong recommendation about the use of |
| Although pain may develop insidiously, many patients | | | | bisphosphonates in the treatment of avascular |
| remember the hour when they first felt incapacitating | | | | necrosis. |