title: Factor V Leiden and the prothrombin 20210A gene mutation and osteonecrosis of the knee.
abstract: BACKGROUND
  The pathogenesis behind osteonecrosis of the knee is still unknown. Circulatory impairment of the bone secondary to thrombosis in the microcirculation has been suggested as a mechanism. The purpose of this study was to examine the association between osteonecrosis of the knee and abnormalities in the thrombotic pathway in the form of factor V Leiden and the prothrombin 20210A gene mutation.
  
  
  METHODS
  Thirty-eight consecutive patients (13 men and 25 women) with osteonecrosis of the knee without a history of knee trauma or surgery to the knee were enrolled in this study. Assays for the detection of factor V Leiden and the prothrombin 20210A gene mutation were performed, and the results were compared with those from 282 healthy volunteers.
  
  
  RESULTS
  Six patients were diagnosed with secondary osteonecrosis, four corticosteroid-induced and two alcohol-induced. In 32 patients, no aetiological factor was found, and these patients were diagnosed with primary osteonecrosis of the knee. Twelve patients had 14 gene mutations, 11 factor V Leiden and 3 prothrombin 20210A gene mutations. Factor V Leiden and the prothrombin 20210A gene mutation occurred significantly (p=0.006) more frequently in patients with osteonecrosis than in a population of 282 healthy volunteers (odds ratio 3.1, 95%CI 1.4-6.6).
  
  
  CONCLUSIONS
  The results of this study suggest that coagulation abnormalities in the form of factor V Leiden and the prothrombin 20210A gene mutation might play a role in osteonecrosis of the knee.
authors.affiliation: Department of Orthopaedics, University Hospital Malmö, 20502, Malmö, Sweden. anders.bjorkman@hand.mas.lu.se
authors.forename: Anders
authors.initials: A
authors.lastname: Björkman
authors.forename: Isabella M
authors.initials: IM
authors.lastname: Burtscher
authors.forename: Peter J
authors.initials: PJ
authors.lastname: Svensson
authors.forename: Andreas
authors.initials: A
authors.lastname: Hillarp
authors.forename: Jack
authors.initials: J
authors.lastname: Besjakov
authors.forename: Göran
authors.initials: G
authors.lastname: Benoni
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D016022:Case-Control Studies; D005165:Factor V / Q000235:genetics*; D005260:Female; D006801:Humans; D007717:Knee / Q000473:pathology*; D008297:Male; D008875:Middle Aged; D010020:Osteonecrosis / Q000235:genetics*; D017354:Point Mutation; D011516:Prothrombin / Q000235:genetics*
chemical_list: C095381:factor V Leiden; D005165:Factor V; D011516:Prothrombin