Quantitative sensory testing in dogs with spontaneous osteoarthritis

James Russell Hunt ¹ David Knazovicky ² Megan Goff ¹ John Harris ³ Toby Knowles ¹ Masataka Enomoto ⁴ Michael Mendl ¹ Becky Whay ⁵ B. Duncan X. Lascelles ^4,6,7,8* Joanna Murrell ^9*

• ¹ Bristol Veterinary School, Faculty of Health Sciences, University of Bristol, Bristol, England, United Kingdom
• ² Department of Clinical Sciences, College of Veterinary Medicine, North Carolina State University, Raleigh, North Carolina, United States
• ³ Division of Animal Sciences, School of Biosciences, University of Nottingham, Sutton Bonington Campus, Loughborough, United Kingdom
• ⁴ Translational Research in Pain, College of Veterinary Medicine, North Carolina State University, Raleigh, United States
• ⁵ Natural Sciences, University of Galway, Galway, Ireland
• ⁶ Center for Pain Research and Innovation, UNC School of Dentistry, Chapel Hill, United States
• ⁷ Center for Comparative Pain Research and Education, North Carolina State University, Raleigh, United States
• ⁸ Center for Translational Pain Medicine, Department of Anesthesiology, School of Medicine, Duke University, Durham, North Carolina, United States
• ⁹ Bristol Vet Specialists, Bristol, England, United Kingdom

Objective: To investigate changes in somatosensory sensitivity in dogs with spontaneous osteoarthritis (OA) and pain of the stifle or hip, compared to a group of healthy control dogs Study design: A non-randomised, non-blinded, prospective research study. Animals: 30 control, 51 OA-pain, and 31 OA-pain dogs receiving NSAIDs Methods: A range of noxious and non-noxious quantitative sensory testing (QST) modalities were applied. Dogs were tested twice, one month apart. Two sites were tested at each visit: a distal site located on the cranial aspect of the mid metatarsus and a primary site, lateral to the patella (in dogs with stifle OA) or craniodorsally to the greater trochanter (in dogs with coxofemoral OA). Control dogs were tested at appropriate primary sites to produce the same proportion of animals being tested at stifle or hip as those in the OA group. The order in which non-nociceptive and nociceptive tests were performed was randomized for each test site for each animal, although nociceptive tests were always performed after non-nociceptive tests. Feasibility for performing the tests was assessed for the final 45 dogs recruited to the study. The hierarchical structure of the QST testing data was accounted for within the statistical analysis by employing general linear modelling within a multilevel modelling framework using the MLwiN statistics package.Results: Osteoarthritis category was not a major determinant of QST outcome measures for the majority of modalities evaluated. In the few modalities in which OA category was determined to be a significant predictor variable, the results were not consistent with previously reported data. The novel, non-nociceptive tests employed overall suggested nonnoxious hypoesthesia in association with OA pain. The feasibility of performing QST assessments was relatively low compared to previous studies.