RESUMEN
We examined the incidence of avascular necrosis (AVN) of the healthy femoral head in unilateral hip dysplasia at the end of the use of the Pavlik harness. The evaluation of AVN was done with the help of standardised roentgenograms. Between 1974 and 1982, 1,064 dysplastic hips (869 children) were treated with the Pavlik harness at the Orthopaedic Department of Semmelweis University. Of these, 674 children who had unilateral hip dysplasia were chosen for this study. In the period of our investigation, ultrasonography was not yet used routinely, so in some cases the hip was mistakenly diagnosed as dysplastic. The average patient age was 3.2 months, and the average length of treatment was 4.9 months. We found no correlation between the appearance of AVN in the healthy hips at the end of treatment with the Pavlik harness and the age of the child at the start of treatment. On the other hand, there was a strong significant correlation between the appearance of AVN and the length of treatment.