Discussion

Tnibar, A., Schougaard, H., Camitz, L., Rasmussen, J., Koene, M., Jahn, W., Markussen, B.
Aims: To investigate the effect of a polyacrylamide hydrogel1 (PAAG) in improving clinical signs of osteoarthritis (OA) in the fetlock or carpus. PAAG is recently used to intra-articularly treat OA in horses. However, no prospective study on the efficacy of PAAG has been reported. Methods: Thirty-three horses older than 2 years with a confirmed OA in only one joint (fetlock or carpus) based on clinical evaluation, intra-articular anaesthesia and imaging (radiography, MRI or arthroscopy) have been included in this clinical trial. Horses were injected with 2 ml of PAAG in the affected joint and were followed up at 1, 3, and 6 months. Efficacy was evaluated by clinical assessment of lameness and joint effusion in the affected joint. Safety assessment of the joint was also evaluated. Data relating to case details, type of activity; joint and leg involved, lameness duration, lameness scoring, joint effusion scoring, radiographic scoring and owner assessment were recorded. Factors associated with the outcome measure 'lameness scoring' were analysed using generalised linear mixed model for logistic regression. Results: Before treatment, the proportion of horses with lameness score 1, 2, 3 and 4 was 27.3%, 33.3%, 33.3% and 6.1%, respectively. The estimated lameness improvement at 1, 3 and 6 months was 81%, 88% and 87%, respectively. At 6 months, approximately 70% (23/33) of horses were lame free. No side effect was observed in the treated joints. There was a significant decrease in lameness score from baseline to 1 month, and from 1 to 3 months, but lameness score was constant from 3 to 6 months. Conclusions and practical significance: Preliminary results show that PAAG significantly alleviated lameness in OA affected joints, as assessed by standard veterinary lameness evaluation. PAAG is a promising and safe treatment for symptomatic OA in horses, and its further evaluation is warranted. Acknowledgements: The authors would like to acknowledge the great help of Bente Brunner. This study has been approved by the Danish Board for Animal Experimentation.