SCIENTIFIC ARTICLE Illness Perceptions of Patients With First Carpometacarpal Osteoarthritis, Carpal Tunnel Syndrome, Dupuytren Contracture, or Trigger Finger Mark J. W. van der Oest, BS, *†‡§ Ralph Poelstra, MD, *†‡ Reinier Feitz, MD,‡ Ana-Maria Vranceanu, PhD,§ Harm P. Slijper, PhD,‡ Ruud W. Selles, PhD, *† The Hand-Wrist Study Group, Jarry T. Porsius, PhD*†‡§ Purpose Previous studies indicate that patients with a more negative perception of their illness tend to respond less favorably to treatment, but little is known about whether illness perceptions differ based on the type of hand or wrist conditions. Therefore, we compared illness perceptions between patients scheduled to undergo surgery for 4 illnesses in hand surgery: carpometacarpal osteoarthritis (CMC OA), Dupuytren disease, carpal tunnel syndrome (CTS), and trigger finger syndrome (TFS). We hypothesized there would be differences in illness perception between these patient groups. Methods Before surgery, patients were asked to complete the Brief Illness Perception Question- naire (Brief-IPQ) as part of routine outcome measurement in a specialized hand and wrist surgery clinic. The Brief-IPQ is a validated questionnaire to rapidly assess the cognitive and emotional representation of illness. Differences in illness perception between the 4 diagnostic groups, cor- rected for age, sex, hand dominance, and work type, were examined. Cohen D effect sizes were calculated for the between-group differences. Results We included 514 patients in the analyses: 87 with CMC OA, 146 with Dupuytren disease, 129 with CTS, and 152 with TFS. On a scale ranging from 0 (most positive perception) to 80 (most negative perception) the Brief-IPQ sum scores for these subgroups were 42.0, 28.2, 38.8, and 33.3, respectively. Corrected for age, sex, hand dominance, and work type, patients with Dupuytren disease had a more positive perception of their illness than patients with CMC OA and CTS. Compared with CMC OA patients, the effect sizes for Dupuytren, CTS, and TFS patients were, respectively, 1.28, 0.32, and 0.81. Conclusions In these patients with various hand/wrist disorders, differences were found in their preoperative perceptions of illness. Interventions that directly target negative illness perceptions might improve treatment outcomes for CMC OA and CTS. Clinical relevance These differences should be considered during preoperative medical consultations and/or when investigating surgical outcomes. (J Hand Surg Am. 2019;-(-):1.e1-e8. Copyright Ó 2019 by the American Society for Surgery of the Hand. All rights reserved.) Key words Illness perception, psychosocial, self-efficacy, expectations. From the *Department of Plastic, Reconstructive and Hand Surgery, Erasmus MC; the †Department of Rehabilitation Medicine, Erasmus MC, Rotterdam; the ‡Hand and Wrist Center, Xpert Clinic, Amsterdam, The Netherlands; and the §Integrated Brain Health Clinical and Research Program, Department of Psychiatry, Massachusetts General Hospital, Harvard Medical School, Boston, MA. Received for publication November 28, 2018; accepted in revised form October 15, 2019. No benefits in any form have been received or will be received related directly or indirectly to the subject of this article. Corresponding author: Mark J.W. van der Oest, BS, Department of Plastic, Reconstructive and Hand Surgery, Erasmus MC, Dr. Molewaterplein 40, Room ee-1589, 3015 GD Rotterdam, The Netherlands; e-mail: m.vanderoest@erasmusmc.nl. 0363-5023/19/---0001$36.00/0 https://doi.org/10.1016/j.jhsa.2019.10.021 Ó 2019 ASSH r Published by Elsevier, Inc. All rights reserved. r 1.e1