The role of coagulation abnormalities in the development of Perthes' disease

Recent reports have suggested an association between Perthes' disease and a n underlying thrombophilic or hypofibrinolytic tendency. In Northern Irelan d there is a high incidence of Perthes' disease (11.7 per 100 000 or 1 in 6 07 children) in a stable paediatric population. We reviewed 139 children with Perthes' disease and compared them with a con trol group of 220 aged- and gender-matched healthy primary schoolchildren w ith similar racial and ethnic backgrounds. There were no significant deficiencies of antithrombotic factors protein C, protein S, antithrombin III or resistance to activated protein C, A total of 53 (38.1%) of the children with Perthes' disease had a prolonged activat ed partial thromboplastin time (> 38) compared with 13 (5.9%) of the contro l group (p < 0.001). Our findings have shown that using standard assays, th rombophilia secondary to antithrombotic factor deficiency or resistance to activated protein does not appear to be an aetiological factor for Perthes' disease. The cause of the prolonged activated partial thromboplastin time, usually associated with a clotting factor deficiency, is under further inv estigation.