Results of retrospective studies1–3 indicate that radiographic evidence of DJD is common in cats. One group found that 64 of 100 cats (mean age, 15 years) had radiographic evidence of what the authors termed appendicular joint osteoarthritis.3 Another investigator found that 22% of 262 cats (mean age, 9.45 years) had radiographic evidence of appendicular joint osteoarthritis2 when at least 1 synovial joint was included on the radiograph. A third study1 found that 16.5% of 218 cats (mean age, 6.5 years) had radiographic evidence of appendicular osteoarthritis. In a prospective study,4 the present authors' laboratory evaluated a randomly selected population of 100 cats (with ages evenly distributed over the range of 6 months to 20 years) and found that 93 cats had radiographic evidence of DJD in some part of the axial or appendicular skeleton (axial skeleton, 53 cats; appendicular skeleton, 92 cats). Results of other studies5–8 suggest that DJD can be associated with signs of pain. However, there are no approved drugs in the United States or proven nondrug methods of providing pain relief to cats affected by DJD. One reason for this may be that there are no validated outcome measures to assess DJD-associated pain in cats. Clinical trials designed to test the efficacy of interventions intended to decrease chronic pain in dogs with DJD have relied heavily on a combination of veterinarian assessment and gait analysis as measured by use of a force plate.9–12 However, subjective veterinarian assessments do not correlate well with force plate data.13,14 Some data suggest that owner assessments may correlate better with force plate results than do veterinarian assessments.15 Furthermore, it has been suggested that overall athletic performance, especially in working dogs, cannot be properly assessed by use of veterinarian-performed orthopedic examinations alone.16 These observations have prompted at least 3 groups to validate chronic pain assessment instruments for dogs that consist of questionnaires completed by the dogs' owners and designed to determine overall function and activity as it relates to signs of chronic pain.17–22 Preliminary work by our laboratory with client-owned cats with obvious signs of pain associated with DJD indicated that owners were able to assess improvement in mobility attributable to the relief of musculoskeletal pain.7 This finding suggested that it is possible to develop a chronic pain assessment instrument for feline DJD-associated pain. The main steps toward this goal are, in order, item generation, readability testing, reliability testing, and validity testing. The purpose of the study reported here was to perform item generation and design testing to create a subjective instrument to assess activity altered by chronic pain caused by DJD in cats.
American College of Veterinary Internal Medicine
American College of Veterinary Surgeons
Body condition score
Brief pain inventory
Canine brief pain inventory
Degenerative joint disease
Numerical rating scale
Visual analogue scale
Canon Medical CXDI-50G Sensor, Eklin Medical Systems, Santa Clara, Calif.
Dell Ultrasharp 2407WFP, Dell, Round Rock, Tex.
eFilm 2.1.2, Merge Healthcare, Milwaukee, Wis.
Clarke S P, Mellor D, Clements DN, et al. Prevalence of radiographic signs of degenerative joint disease in a hospital population of cats. Vet Rec 2005; 157:793–799.
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