Osteonecrosis of the Hip and Bisphosphonate Treatment
Status:
Unknown status
Trial end date:
2013-12-01
Target enrollment:
Participant gender:
Summary
Osteonecrosis of the hip is an important cause of musculoskeletal disability and finding
therapeutic solutions has proven to be challenging. Osteonecrosis means death of bone which
can occur from the loss of the blood supply or some other means. Although any age group may
develop osteonecrosis, most patients are between 20 and 50 years old. The most common risk
factor is a history of high steroid treatment for some medical condition. The next most
common associated condition is a history of high alcohol use. There are some cases of
osteonecrosis that occur in patients that are otherwise completely healthy with no detectable
risk factors.
In the earliest stage of the disease, x-rays appear normal and the diagnosis is made using
MRI. The advanced stages of osteonecrosis begin when the dead bone starts to fail
mechanically through a process of microfractures of the bone. As the disease progresses, the
surface begins to collapse until, finally the integrity of the joint is destroyed. A wide
range of surgical treatments with variable success rates have been proposed for the treatment
of the osteonecrosis to preserve joint integrity, including core decompression, whereby the
venous hypertension that ensues is lessened and revascularisation may be induced leading to
bone repair. Nonsurgical treatment options are limited and usually result in a poor
prognosis. Early stage disease can be treated with protected weight bearing and
physiotherapy, however some studies have shown protected weight bearing to be associated with
a greater than 85% rate of femoral head collapse. Unfortunately most studies indicate that
the risk for disease progression is greater with nonsurgical treatment than with surgical
intervention. There are no established pharmaceuticals for the prevention of treatment of
osteonecrosis. Evidence is increasing that the nitrogen containing bisphosphonates may be
beneficial in the treatment of osteonecrosis. One bisphosphonates (alendronate) has been
evaluated in 60 patients diagnosed with osteonecrosis of the hip. Recent clinical studies
have shown very promising results. All patients had symptomatic improvement after one year.
Although the follow up time ranged from 3 months to 5 years, only 6 patients progressed to
the point of needing surgery.