Intra-articular 2.5% polyacrylamide hydrogel provides sustained clinical improvement over 1 year in canine elbow osteoarthritis.

OBJECTIVE

To evaluate the efficacy, safety, and tolerability of IA 2.5% injectable polyacrylamide hydrogel (iPAAG) in dogs with elbow osteoarthritis (OA). We hypothesized that treatment would improve pain and function, with minimal adverse events.

METHODS

This prospective single-site clinical study enrolled client-owned dogs from October 2023 to October 2024. Dogs with elbow OA confirmed by CT received unilateral or bilateral IA injections with 1 mL of 2.5% iPAAG. Assessments were conducted on day 0 (baseline) and at 2 weeks, 1 month, 3 months, 6 months, and 12 months after injection using the Canine Brief Pain Inventory (CBPI) Pain Severity Score, CBPI Pain Interference Score, modified Glasgow Composite Pain Scale, Numerical Rating Score, elbow goniometry, thoracic limb girth, and joint effusion. Complete blood count and serum biochemistry were performed at baseline and 3 months after injection.

RESULTS

18 dogs were treated; 16 completed the study. There were significant improvements in all measures between baseline and 3 to 12 months. The CBPI Pain Severity Score, CBPI Pain Interference Score, modified Glasgow Composite Pain Scale, Numerical Rating Score, elbow flexion, elbow extension, thoracic limb girth, and joint effusion had an overall effect size of 0.44, 0.53, 0.69, 0.63, 0.31, 0.64, 0.53, and 0.64, respectively. There were minimal, self-limiting adverse events and no clinically significant changes in blood work.

CONCLUSIONS

2.5% iPAAG appears to be well tolerated, safe, and effective for the IA treatment of canine elbow OA. Study limitations included a small sample size and lack of control group.

CLINICAL RELEVANCE: These findings support 2.5% iPAAG as a targeted therapy for canine elbow OA. Further research is warranted to evaluate histological effects.