Most recent publication on assessing pain sensitisation in osteoarthritis (OA) provides new tools for evaluating durg efficacy in OA:  Arendt-Nielsen L, Nie H, Laursen MB, Laursen BS, Madeleine P, Simonsen OH, Graven-Nielsen T. Sensitization in patients with painful knee osteoarthritis. Pain. 2010 Jun;149(3):573-81.