Femoral head osteonecrosis is the death of bone at the top of the femur (thighbone). It can occur after trauma in children and has a poor outcome. In this study, doctors at the Children’s Hospital at Westmead in Australia try a new treatment to prevent this from happening.
This is the first study in children to use bisphosphonates to prevent osteonecrosis. Bisphosphonates are a class of anti-resorption drugs used for bone cancer patients or for osteoporosis in older adults. Anti-resorptive means they keep the bone from breaking down. They also can improve bone density. So far, only animal and human adult studies have been done.
Children who had surgery for slipped capital femoral ephiphysis (SCFE), femoral neck fractures, or hip dislocation were included. Bone scans were done to detect osteonecrosis. Bisphosphonate therapy was started in any child who had a positive bone scan.
The drug was given intravenously (IV). This method of delivery helps improve absorption. More of the drug is available for use in the body compared with taking an oral dose in pill form. IV administration also made sure the child got the medication.
The children were monitored every three months for at least two years. X-rays and an exam were done to watch for complications. There were no major adverse effects of the drug. No negative effects on growth were seen in the children. The use of bisphosphonates was successful in all children included in the study.
The authors saw signs of bone resorption for up to 18 months after the initial injury. They suggested a higher dose of drug may have been needed. Right now the best dose and duration of bisphosphonate to use is unknown. Further study is needed to find the right balance to protect bone without increasing the risk of adverse side effects.