Maxim Moreau, Eric Troncy, Sylvain Bichot, Bertrand Lussier.
Universite de Montreal, St-Hyacinthe, QC, Canada

ACVS Abstract 2007

Ground reaction forces (GRF) data acquired by a force platform allow an objective method to capture treatment effects using a refined procedure. Hence, the quality of GRF data has been enhanced when expressed in percentage of the dog’s body weight (%BW). Our objective was to address complementary peak vertical force (PVF) analyses after having recorded a gain in BW in dogs with osteoarthritis (OA), thus raising the hypothesis of a bias in study outcome.

Twenty six lame client-owned dogs afflicted by OA were evaluated in a unilateral crossover design. Dogs were fed with two different veterinary diets for subsequent periods of 30 and 60 days. Dogs recruited showed radiographic evidence of OA and had abnormal PVF at Day 0, as supported by orthopedic examinations. Peak vertical force was also acquired at Day 30 and 90 at a constant trotting velocity. Significance level was set at 5%. A significant change in PVF (ANOVA) was not detected between Day 0 (63.90%BW), Day 30 (65.55%BW) and Day 90 (66.48%BW). However, a significant increase in BW was observed at Day 90 (41.33 kg) when compared to Day 30 (39.98 kg) and Day 0 (39.94kg). A significant negative correlation (Spearman test) was observed, meaning a decrease in PVF when an increase in BW was recorded.

In addition, a significant effect of the BW (ANCOVA) was recorded on PVF values. Adjusted PVF according to BW were then 63.37, 64.98 and 67.57%BW at Day 0, 30 and 90, respectively. Peak vertical force values recorded at Day 0 and at Day 90 were significantly different. These additional analyses demonstrated that a gain in BW was detrimental in dogs afflicted by OA while highlighting the need to keep BW constant when using GRF to capture treatment effects. These findings sustained the deleterious gain in BW for joint integrity, joint support and its potential to exacerbate lameness associated to OA.