Protein C levels in patients with Legg-Calve-Perthes disease: is it a true deficiency?

A hyper-coagulable state due to protein C deficiency has been postulated to be the cause of avascular necrosis of the capital femoral physes in Legg-Calve-Perthes disease (LCPD). In order to test this hypothesis, plasma protein C levels were analyzed from 51 unselected cases of LCPD. These were compared with a control group. Our findings showed that the levels were less than the mean for age in 38 (74.5%) of the cases, though were within the normal range. We conclude that clinical thrombosis could be triggered off in these susceptible individuals by prothrombotic insults such as passive smoking, ultimately leading to LCPD.