An international multi-centre prospective study on the efficacy of an intraarticular polyacrylamide hydrogel in horses with osteoarthritis: a 24 months follow-up

Abstract

BackgroundPolyacrylamide hydrogel (PAAG) was evaluated recently to treat osteoarthritis (OA) in horses with highly encouraging results; however no long term field-study was done to explore its clinical efficacy and lasting effect. The objective of this study was to evaluate the efficacy of PAAG in improving clinical signs of OA in horses. We hypothesized that lameness grade would significantly improve and the effect would last at least 2 years in osteoarthritic joints treated with PAAG. Forty three horses older than 2 years with OA in only one joint based on clinical evaluation, intra-articular anaesthesia and imaging (radiography) were included in this study. Horses were injected with 2 ml of PAAG into the affected joint and were followed up at 1, 3, 6, 12 and 24 months. Efficacy of PAAG was evaluated by blinded clinical assessment of lameness. Adverse reactions to joint injection were assessed. Data relating to case details, type of activity, joint and limb involved, lameness duration, lameness grading, previous joint treatment, joint effusion grading, radiographic grading, and owner assessment were recorded. Factors associated with the outcome measure “lameness grading” were analyzed using generalized linear mixed model for logistic regression.ResultsAt 1, 3, 6, 12 and 24 months follow-up, 59%, 69%, 79%, 81/% and 82.5% of horses were non-lame respectively. Reduction of joint effusion was observed over time. No side effect was observed in the treated joints. There was a significant decrease in lameness grade from baseline to 1, 3, 6, 12 and 24 months (P < 0.0001) and a significant positive association with joint effusion (P < 0.0001). Estimates for odds ratio (OR) showed that the effect of treatment increased over time (OR for lower lameness from month 1 to month 24 relative to baseline increased from 20 to 58).ConclusionsPAAG significantly alleviated lameness and joint effusion in osteoarthritic joints. PAAG is a safe and lasting (at least 24 months) OA treatment in horses. PAAG is a promising new treatment for OA in horses.

A Survey of Clinical Usage of Non-steroidal Intra-Articular Therapeutics by Equine Practitioners

“…Our results indicate that practitioners outside the USA more frequently used polyacrylamide hydrogel than practitioners in the USA. Investigations into the use of polyacrylamide hydrogel have been primarily based out of Europe (31,32), where it has been available on the market for a longer time period than in the USA. These factors indicate that practitioners outside the USA are likely more familiar with the product and have had more opportunities to use this product than practitioners in the USA.…”

Synovial incorporation of polyacrylamide hydrogel after injection into normal and osteoarthritic animal joints

“…Analgesic benefits for PAAG have been reported in an observational study in the horse, where one treatment of 2 ml PAAG in fetlock or carpus joints was found to have a significant effect on lameness and effusion during the first month post treatment, after which this effect increased progressively until 6 months, and then stabilized up until 24 months 12 . Recently an observational pilot study of 60 human knees with OA, which were treated with nondegradable PAAG, showed promising results for pain reduction 13 .…”

“…Five joints without OA served as controls. The horses were part of a large prospective clinical study carried out at three different equine centers, where 1e4 (mean 2) ml of PAAG had been injected per joint and where the effect of the treatment was followed postoperatively for up to 2 years 12 . Histopathological examination was carried out on leg joints from horses having died during that period.…”

“…In a preliminary study, PAAG demonstrated analgesic benefits in equine OA joints up to 2 years post injection 12 . In order to understand any potential mechanism of action of PAAG, the first step would be to demonstrate if the gel was retained over the duration of purported benefit, and where the gel would be located following injection (joint cavity or tissues).…”

Efeito terapêutico do pentosan polisulfatado sódico sobre a osteoartrite de equinos

“…E também o hidrogel de poliacrilamida (PAHG), que são frequentemente utilizados e associados com o efeito anti-inflamatório, proteção osteocondral e regeneração, melhora da viscosidade e da mobilidade articular (TNIBAR et al, 2015;FRISBIE et al, 2016;SOUZA, PARETSIS & ZOPPA, 2020).…”