Factor V Leiden and the prothrombin 20210A gene mutation and osteonecrosis of the knee.

INTRODUCTION

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.

MATERIALS AND

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).

CONCLUSION

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.