Research Article Establishing the Psychometric Properties of the ICOAP Questionnaire through Intra-Articular Treatment of Osteoarthritic Pain: Implementation for the Greek Version George E. Manolarakis, 1,2 Nick Kontodimopoulos, 1 Dimitra Sifaki-Pistolla, 3 and Dimitris Niakas 1 1 Faculty of Social Sciences, Hellenic Open University, Patras, Greece 2 Sitia’s General Hospital, Sitia, Crete, Greece 3 Medical School, Department of Social Medicine, University of Crete, Heraklion, Crete, Greece Correspondence should be addressed to George E. Manolarakis; gem2017@med.cornell.edu Received 21 September 2015; Revised 30 December 2015; Accepted 28 January 2016 Academic Editor: Henning Bliddal Copyright © 2016 George E. Manolarakis et al. Tis is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Objectives. In this prospective study, we intend to establish the psychometric properties of ICOAP for its use in studies involving the Hellenic population. Methods. SF-36 Health Survey was used as a standard against ICOAP scores from a sample of 89 patients (mean age: 71.07, 69 females) with hip and knee OA pain who underwent 2 treatment cycles of 4 intra-articular injections of sodium hyaluronate, separated by a 12-week medication-free time interval. Both questionnaires were flled twice with no missing data during follow-up. Results. ROC analysis accomplished ICOAP’s criterion-related validation. Wilcoxon Signed-Rank Test and paired samples -test endorsed ICOAP’s responsiveness along with Efect Size values, standard response mean, and Relative Efciency. Comparisons between the areas under curves (AUC) on ROC plots established external responsiveness. Cronbach’s-alpha value favored ICOAP’s internal consistency. Tis, along with intraclass correlation, results in both advocated reliability and content validity. Interitem discrimination was demonstrated by the ease of completion of ICOAP as well as the degree of familiarity with it. Tese fndings inaugurated construct validity in collaboration with Spearman’s and One-Way ANOVA results. Conclusions. ICOAP is a valid, reliable, and responsive QoL instrument and suitable for studies of osteoarthritic joint pain in the Greek setting. 1. Introduction During recent decades, the ongoing increase in life expectancy has shifed the interest of health professionals towards new ways of disease management. In the case of osteoarthritis (OA), this interest addresses the most important need of every arthritic patient: to live a pain-free life at the lowest functional compromise. Keeping in mind a variety of conservative and surgical treatment methods that are still in use, it becomes obvious that osteoarthritic pain comes into play as a major health- related quality of life (HRQoL) determinant that challenges any country’s health system efciency in terms of burden of disease. Among developed HRQoL questionnaires focused on osteoarthritic pain, the Intermittent and Constant Osteoarthritis Pain (ICOAP) questionnaire for hip and knee osteoarthritis, a relatively new assessment tool, is the frst to introduce the distinction of OA hip and knee pain in its two components: constant (ICOAP-CP) and intermittent (ICOAP-IP) pain. Tis distinction provides detailed information for each of these two kinds of pain separately as well as for total pain, thus forming a global view which difers from “pain on activity” as measured by all the preexisted questionnaires [1]. In this study, we attempt to establish the psychometric properties, namely, validity, reliability, and responsiveness, of the Greek version of the ICOAP questionnaire from a sample Hindawi Publishing Corporation Arthritis Volume 2016, Article ID 6201802, 11 pages http://dx.doi.org/10.1155/2016/6201802