[1] Leiden Univ, Dept Rheumatol, Med Ctr, NL-2300 RC Leiden, Netherlands
[2] Leiden Univ, Dept Orthoped, Med Ctr, NL-2300 RC Leiden, Netherlands
[3] Centocor Inc, Horsham, PA USA
[4] TNO Qual Life, Business Unit Med Res, Leiden, Netherlands
[5] Erasmus MC, Dept Orthoped, Rotterdam, Netherlands
[6] Leiden Univ, Dept Clin Epidemiol, Med Ctr, NL-2300 RC Leiden, Netherlands
[7] Leiden Univ, Dept Gen Internal Med, Med Ctr, NL-2300 RC Leiden, Netherlands