Recruitment originated from 5 sources:
(1) outpatient OA clinics of the
Department of Orthopedic Surgery,
UMCG, and the Department of
Orthopedic Surgery, Martini Hospital,
Groningen, the Netherlands; (2)
general practitioners in areas near
the AHCRR and at the Department of
General Practice, UMCG; (3) people
who presented directly to the
AHCRR and met the inclusion criteria,
as established by their general
practitioners; (4) local paper advertising;
and (5) website advertising at
UMCG,