The role of protein C deficiency in the etiology of Perthes disease.

BACKGROUND Recent reports support the hypothesis that thrombophilia plays an important role in the pathogenesis of Perthes disease (PD) and the objective of this report is to show evidence of the role of protein C deficiency in the etiology of PD, based on a meta-analysis of current scientific literature. MATERIAL AND METHODS Studies were selected in all languages over the last twenty years (1986 to 2006) in MEDLINE, LILACS and EMBASE data bases. The inclusion criteria involved controlled studies, those that presented protein C as a continuous variable, and studies conducted in children with Perthes disease. The fixed effect model for continuous data was used; differences between groups were assessed by the t-test, Z-test and Cochran Q test for independent data and the level of significance was p < 0.05. RESULTS The selected studies involved 175 patients and 193 control subjects. The selected studies were shown to be heterogeneous, but there were no statistically significant differences in protein C levels between groups. CONCLUSION The authors' findings were unable to support the hypothesis that protein C deficiency is associated with Perthes disease and that it may play an important role in the ethiopathogenesis of avascular necrosis of the femoral head in childhood.