The investigators at St. Jude Children’s Research Hospital found that if more than 30 percent of the head of the bone fitting into the hip socket is deteriorated, it is at high risk of collapsing and requiring reconstructive surgery within two years.

The study is significant because the intensive use of corticosteroid drugs that have been implicated in development of osteonecrosis, or bone deterioration, is a major component of chemotherapy for paediatric leukaemia and lymphoma. The drugs have been key to raising the survival rates of children with these cancers, and currently there is no adequate substitute for their use. Therefore, it is important for clinicians to monitor patients during treatment and identify those at highest risk for this complication.

“Being able to predict which children are likely to experience serious bone deterioration in the future will help investigators identify and monitor survivors who are at particularly high risk for developing this problem,” said Sue Kaste, D.O., a member of the Radiological Sciences department at St. Jude. “Osteonecrosis has become one of the most important side effects of therapy that affects the quality of life of these long-term survivors,” she said.

The St. Jude team reviewed the medical records and MRI images of 80 patients who developed osteonecrosis of the capital femoral epiphysis to identify factors that appeared to be linked to the future collapse of the bone’s surface and the need for arthroplasty.

A total of 23 of the 80 patients, or 29 percent, eventually underwent arthroplasty for one or both hips at an average of 1.3 years after diagnosis of osteonecrosis. In cases in which necrosis involved more than 30 percent of the head of the hip, 80 percent of the hips collapsed within two years after osteonecrosis was identified, with 50 percent requiring arthroplasty.; Source: St. Jude Children's Research Hospital