Characterization of osteoarthritis in cats and meloxicam efficacy using objective chronic pain evaluation tools

Abstract

This study aimed to characterize osteoarthritis (OA)-related chronic pain and disability in experimental cats with naturally occurring OA. Peak vertical ground reaction force (PVF), accelerometer-based motor activity (MA) and the von Frey anesthesiometer-induced paw withdrawal threshold were used to define OA and to test the efficacy of meloxicam. A diagnosis of OA was based on radiographic and orthopedic examinations. Cats with OA (n=39) and classified as non-OA (n=6) were used to assess the reliability and sensitivity of the parameters to assess OA over 3weeks while being administered placebo medication. A randomised parallel design study was then used to investigate the effects on OA of daily oral meloxicam treatment for 4weeks at different dose rates (0.025mg/kg, n=10mg/kg; 0.04mg/kg, n=10; 0.05mg/kg, n=9), compared to cats administered a placebo (n=10). The test-retest repeatability for each tool was good (intra-class correlation coefficient ⩾0.6). The PVF and the von Frey anesthesiometer-induced paw withdrawal threshold discriminated OA (P<0.05). Meloxicam did not add to the PVF improvement observed in placebo-treated cats during the treatment period (adj-P⩽0.01). The 0.025 and the 0.05mg/kg meloxicam-treated cats experienced a higher night-time (17:00-06:58h) MA intensity during the treatment period compared to the placebo period (adj-P=0.04, and 0.02, respectively) and this effect was not observed in the placebo group. The high allodynia rate observed in the 0.04mg/kg meloxicam-treated group may explain the lower responsiveness to the drug. The von Frey anesthesiometer-induced paw withdrawal threshold demonstrated no responsiveness to meloxicam. The results from this study indicated that daily oral meloxicam administration for 4weeks provided pain relief according to night-time MA.

[18F]-fluorodeoxyglucose positron emission tomography of the cat brain: A feasibility study to investigate osteoarthritis-associated pain

“…This finding was interpreted as an increase in activity of the descending facilitatory pathways. In line with the hypersensitivity (Guillot et al, 2013) and facilitation of temporal summation (Guillot et al, 2014) observed in OA cats, the enhanced brain metabolism in the thalamus and PAG observed in OA cats may also represent increased activity of the descending facilitatory pathways.…”

“…The extent of radiographic OA was graded by a veterinary radiologist: osteophytes and enthesiophytes were scored together according to their global size (0-3); subchondral sclerosis was scored according to its extent (0-3); and joint effusion was identified and was scored as normal (0) or increased (1) (Guillot et al, , 2013. Each joint was graded and the radiographic score was defined for forelimbs and hind limbs as the sum of the score of their joints (Table 1).…”

“…Our group previously demonstrated that, when compared with non-OA cats, those with OA pain presented a punctate tactile hypersensitivity (Guillot et al, 2013) and a facilitation of nociceptive temporal summation (Guillot et al, 2014), both recognized to reflect central sensitization (Woolf, 2011). Other central changes can occur with chronic pain such as alterations in CNS activity and in cognition and affect (Kuner, 2010).…”

Systematic review of ground reaction force measurements in cats

“…The authors found that the average value of both hindlimb PFz was higher in normal cats than in cats with OA and that PFz was positively correlated with the mean motor activity, as measured by accelerometer-based activity sensors attached to the cats' collars. In a subsequent study, Guillot et al (2013) used accelerometer-based motor activity (the von Frey anesthesiometer-induced paw withdrawal threshold) and PFz measurements to characterise OA-related chronic pain and disability in 39 cats with naturally occurring OA to evaluate the efficacy of meloxicam treatment. The diagnosis of OA was confirmed by radiography and clinical examination in 29 cats and by clinical examination only in 10 cats.…”

Low-field magnetic resonance imaging of changes after femoral osteosynthesis failure: a case report

“…Osteoarthritis occurs frequently in cats, but it is rarely diagnosed (Clarke et al 2005;Lascelles 2010;Guillot et al 2013). Degenerative changes are most often observed in elbow joints, followed by hip and stifle joints (Guillot et al 2012).…”