A Preliminary Field Trial Evaluating the Efficacy of 4% Polyacrylamide Hydrogel in Horses With Osteoarthritis

Intra-articular polyacrylamide hydrogel is being investigated for the treatment of osteoarthritis (OA) in multiple species. A 4% polyacrylamide hydrogel has been evaluated in humans with positive results. A field trial using 4% intraarticular polyacrylamide hydrogel in equine joints with naturally occurring OA is indicated to determine the effectiveness of this therapy. The objective of this field trial is to investigate the effect of intra-articular 4% polyacrylamide hydrogel in horses with naturally occurring OA. Horses were selected for inclusion in the study based on a lameness examination including intra-articular localization and radiographic examination. Twenty-eight horses that met study criteria were included in the primary outcome evaluation. For primary outcome, success was defined as at least one grade decrease in lameness and/or a combined reduction of at least three grades among the scores for pain, range of motion, and joint swelling from treatment to day 45. There was a significant (P < .001) decrease in median (range) lameness score from 2 (1-4.5) to 1 (0-3) with 23/28 (82%) of the horses improved based on study criteria. In addition, 21/28 (75%) of the horses met study criteria for success at day 90. Throughout the study period, there were 43 injections of polyacrylamide hydrogel, which included eight horses that had the material administered two times, and there were no adverse events recorded in any horses. The limitation of this study was that there was no control group, and the study follow-up was maximum 90 days.