title: Reply.
authors.affiliation: International Consortium for Health Outcomes Measurement, Cambridge, Massachusetts.|Sahlgrenska Academy, University of Gothenburg, Gothenburg, Sweden.
authors.forename: Ola
authors.initials: O
authors.lastname: Rolfson
authors.affiliation: Connecticut Joint Replacement Institute, Hartford, Connecticut.
authors.forename: John
authors.initials: J
authors.lastname: Grady-Benson
authors.affiliation: Lund University, Lund, Sweden.
authors.forename: Leif E
authors.initials: LE
authors.lastname: Dahlberg
authors.affiliation: University of Massachusetts Medical School, Worchester, Massachusetts.
authors.forename: Patricia D
authors.initials: PD
authors.lastname: Franklin
authors.affiliation: Aneurin Bevan Health Board, Newport, UK.
authors.forename: Sally
authors.initials: S
authors.lastname: Lewis
authors.affiliation: University of Melbourne, Melbourne, Australia.
authors.forename: Ilana N
authors.initials: IN
authors.lastname: Ackerman
mesh_terms: D032921:Consensus; D006801:Humans; D020370:Osteoarthritis, Knee; D017063:Outcome Assessment, Health Care