Obesity and osteoarthritis (OA) both cause significant health problems in dogs. This study used client-owned dogs to evaluate the effect of weight loss on lameness. Severity of lameness was assessed subjectively using a numeric rating scale (NRS) and a visual analog scale (VAS) and objectively using a kinetic gait analysis. Fourteen dogs, ranging in age from 10 months to 6.8 years completed the study. All had clinical signs of lameness and radiographic evidence of OA at the beginning of the study and body weight at least 20% over ideal weight. The dogs were placed on a weight loss program using commercially available foods and monitored for 18 weeks. They were evaluated 2 weeks apart for 6 visits and 4 weeks apart for the last 2 visits. At each visit body weight and pelvic circumference were measured and severity of lameness was evaluated. The NRS and VAS were given for a walk and a trot. If multiple limbs were affected, the investigators determined which limb was most significantly affected, and that limb was scored for the remainder of the study. Dogs had lost an average 8.6% of their body weight and 6.92% of their initial pelvic circumference by the end of the study. A significant reduction of lameness as assessed by the NRS and VAS was seen with a weight loss of 6.10% and upward. Kinetic gait analysis supported this at a weight loss of 8.85% or more. Average VAS lameness scores were significantly different from the second visit onward.

Commentary: This is indeed good news for pet owners. It is sometimes hard to obtain an owner’s commitment to start or stay on weight loss programs for his or her dog. If the dog is obese and has OA, these results are encouraging. What better incentive than to see the improvement in lameness at each recheck visit? The dogs in this study lost 0.55% of their body weight per week, which is near the recommendation for safe weight loss.—Patricia Thomblison, DVM, MS

The effect of weight loss on lameness in obese dogs with osteoarthritis. Marshall WG, Hazewinkel HAW, Mullen D, et al. VET RES COMMUN 34:241-253, 2010.