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In its early stages, there are usually no symptoms associated with osteonecrosis, or avascular necrosis (AVN). It often progresses as a painful, debilitating disease.
When the hip is involved, total joint replacement is likely.
“We know about osteonecrosis and its association with alcohol abuse, systemic corticosteroid use, lupus, sickle cell anemia, and traumatic hip fractures,” said Dr. Galen Joe, senior staff fellow in the CC’s Rehabilitation Medicine Department and a collaborator on the investigation. “This study concluded that HIV-infected patients in this cohort are at a higher risk for developing AVN of the hip. That finding was unexpected.”
Why the hip? Simple anatomy is part of the answer. Dr. Joe notes. Blood vessels surrounding portions of the hip travel what’s essentially a dead-end street. “Due to the limited collateral blood flow to the femoral head, the blood supply is easily compromised. When this nutrient blood flow is impaired, bone tissue may die. It tries to repair itself but it frequently can’t and eventually collapses.”
Early on, osteonecrosis is what Dr. Joe describes as “clinically silent.” His aim is to break that silence by looking for better ways to use the physical exam to pick up early clues to the disease’s presence and to identify interventions that will help preserve daily functioning in patients found to have osteonecrosis. Pain and/or stiffness are the primary symptoms patients report. Standard X-rays and MRI scans can confirm the diagnosis, but X-rays often miss the disease in its early stages.
A subset of 176 patients in the study had functional histories and physical exams performed.
“We tested muscle strength, range of motion, and evaluated pain with movement around the hip joint. These are often clues to a problem. If we know there is a predisposition, just as with any disease process, it is important to make an early diagnosis with cost- effective screening and begin treatment when indicated,” he said.
—by Sara Byars