Osteonecrosis
from The National Osteonecrosis Foundation and
The Center for Osteonecrosis Research and Education website
Osteonecrosis means death of bone which can occur from the loss of the blood supply or by some other means. It has been known by a number of other names including ischemic necrosis of bone, aseptic necrosis or avascular necrosis (AVN). AVN has been quite popular in its use because it is shorter to say and write. More recently the term ON (osteonecrosis) has been adopted.
Unfortunately many patients with ON have had the disease for quite some time before symptoms are present. The initial symptoms are usually felt during activity and include pain or aching in the affected joint. Symptoms usually begin slowly and may initially be sporadic. Sometimes, the pain may begin quite suddenly. As the disease progresses, the pain increases and is associated with stiffness and loss of motion of the involved joint. Limping becomes common. The hip is the most common joint affected, and the pain is usually felt in the groin.
There are no established pharmaceuticals (drugs) for the prevention or treatment of osteonecrosis. In order to treat the disease, we must first understand how the disease develops. In spite of considerable effort by researchers, we still do not know for sure what causes some forms of osteonecrosis (that is, the forms that are not a result of a fracture or radiation).
Bisphosphonates
Bisphosphonates are a class of drugs that have been used to treat osteoporosis – a disease that is characterized by a low bone mass. Recently, in an effort to reduce bone loss, one bisphosphonate - alendronate has been evaluated in 60 patients diagnosed with osteonecrosis of the hip10. All patients had symptomatic improvement at one year. Although the follow-up time ranged from three months to five years, only six patients (ten hips) progressed to the point of needing surgery. It is important to note that these patients were also instructed to avoid bearing weight on their affected hip. Recently, concern has been raised relating to a possible association between bisphosphonate therapy and an increased incidence of osteonecrosis of the jaw11,12. Further study is needed to clarify this possible complication.
http://www.nonf.org/nofbrochure/nonf-brochure.htm
Tags: Bisphosphonates, Osteonecrosis, Osteoporosis