Evaluation of intra-articular injection of collagen-elastin hydrogel microparticles for managing osteoarthritis-associated elbow pain in dogs: a double-blind, positive-controlled clinical trial

Gabriella CastroLindsay Hochman ElamFelix Michael Duerr^*

• Colorado State University, Fort Collins, United States

This double-blind, positive-controlled clinical trial was designed to evaluate the tolerance and efficacy of a commercially available injectate made of collagen-elastin hydrogel microparticles (CEHM). Thirty-five client owned dogs with naturally occurring bilateral elbow osteoarthritis (OA) were randomized into two study groups receiving a single intra-articular injection into both elbows: Triamcinolone (TA) + CEHM or TA only. Eighteen dogs were treated with TA + CEHM; 17 were treated with TA only. All patients were required to be on consistent non-steroidal anti-inflammatory drugs (NSAIDs) at the time of enrollment and were instructed to discontinue before injection. Patients were evaluated at seven timepoints over a one-year period. Outcome measures included veterinary assessment, objective gait analysis (OGA), accelerometry, and clinical metrology instruments (Canine Brief Pain Inventory and Client Specific Outcome Measures). Individual patient success was predefined based on previous literature as specific improvements in four out of five of the following outcome measures: Veterinary assessment, OGA, accelerometry, Canine Brief Pain Inventory Pain Interference Score, and Canine Brief Pain Inventory Pain Severity Score. Thirty-three patients were included for at least partial data analysis. Adverse effects associated with TA + CEHM included three mild and two moderate cases of transient soreness. Two mild cases of transient soreness were reported in the TA group. All adverse events resolved without treatment. There was insufficient evidence to conclude a difference between groups for any of the response variables. As expected, clinical metrology instruments improved significantly in both groups. Eighty-two percent (14/17) of dogs in the TA + CEHM group restarted NSAIDs, compared to 56% (9/16) of dogs in the TA group. The proportion of dogs reaching individual patient success was low and ranged from 0-29% across the study time points. Given the lack of difference between groups, further research, with larger sample sizes, is needed to justify the use of these products in dogs for the treatment of elbow OA.