Abstract
The therapeutic approach for the treatment of children with radiologically "normal" hip presenting with epiphysiolysis of the contralateral upper femur is controversial. We here report the case of a 12-year-old boy with osteonecrosis of radiologically "normal" and asymptomatic left femoral head prophylactically fixed due to acute femoral epiphysiolysis of the contralateral hip. Eight months after first surgery, the patient developed symptoms of avascular osteonecrosis of the femoral head. Specific criteria to be used in evaluating the most effective treatment between preventive screw or simple close monitoring exist. Despite these criteria, the risk of osteonecrosis in the "healthy" hip is not zero.