Abstract
Background: Osteoarthritis (OA) is common in dogs and causes chronic pain that affects quality of life and may not respond to analgesics.
Objective: To determine whether low-level laser therapy (LLLT) would improve quality of life, and help reducing systemic analgesics, in dogs with OA.
Methods: Seventeen client-owned dogs diagnosed with OA and associated pain were included; the diagnosis of OA was confirmed by orthopaedic and radiographic examination. Pain was evaluated in each dog with the Canine Brief Pain Inventory (CBPI), compiled by the dog owners, as well as with a Visual Analogue Scale (VAS) and the Colorado State Canine Chronic Pain Scale, used by the clinician. Low-level laser therapy was performed weekly in each study dog, for a total of six week-period. The CBPI was then repeated at two, four, six and eight weeks after the first laser session, while the VAS was reassessed at weeks two and six. The dogs were observed for occurrence of laser-related side effects.
Results: Both CBPI and VAS were significantly reduced after the first laser session (9.2 ± 3.8 and 5.2 ± 1.1, respectively) compared to pre-treatment values (11.8 ± 3.6 and 7.6 ± 0.9; P = .018 and P < .001, respectively) and continued to decrease over time until the end of the therapy. Based on these results and on improved function, as assessed by the orthopaedic surgeon, the pharmacological analgesic therapy was reduced by the clinician at week two in 13 out of 17 dogs. Laser-related side effects were not observed.
Conclusion: This retrospective report provides a basis for future investigations, needed to clarify whether laser therapy may be beneficial to treat canine OA-associated pain. The preliminary findings are promising and suggest that LLLT may help reducing the analgesics administration and improving client satisfaction and quality of life of dogs with OA.

Key words: Canine osteoarthritis, chronic pain, low-intensity laser therapy, LILT, orthopaedic pain