title: An international multi-centre prospective study on the efficacy of an intraarticular polyacrylamide hydrogel in horses with osteoarthritis: a 24 months follow-up.
abstract: BACKGROUND
  Polyacrylamide 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.
  
  
  RESULTS
  At 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).
  
  
  CONCLUSIONS
  PAAG 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.
authors.affiliation: Department of Large Animal Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Hoejbakkegaard alle 5, DK-2630, Taastrup, Denmark. aztnibar@gmail.com.
authors.forename: Aziz
authors.initials: A
authors.lastname: Tnibar
authors.affiliation: Noerlund Hestehospital, Roedebækvej 2, DK-8653, Them, Denmark. mail@hestehospitalet.dk.
authors.forename: Hans
authors.initials: H
authors.lastname: Schougaard
authors.affiliation: Camitz equestrian, Aasoe Mosevej 13, DK-4171, Glumsoe, Denmark. camitz@mail.dk.
authors.forename: Linus
authors.initials: L
authors.lastname: Camitz
authors.affiliation: Hoejgaard Hestehospital, Rugaardsvej 696, DK-5462, Morud, Denmark. jr@hoejgaard-hestehospital.dk.
authors.forename: Jonas
authors.initials: J
authors.lastname: Rasmussen
authors.affiliation: Tieraerztlische Klinik fuer Pferde, Essener Strasse 39a, D-49456, Bakum, Germany. mkoene@tierklinik-luesche.de.
authors.forename: Marc
authors.initials: M
authors.lastname: Koene
authors.affiliation: Pferdeklinik Bargteheide, Alte Landstrasse 104, D-22941, Bargteheide, Germany. w.jahn@pferdeklinik-bargteheide.de.
authors.forename: Werner
authors.initials: W
authors.lastname: Jahn
authors.affiliation: Department of Mathematical Sciences, Laboratory of Applied Statistics, University of Copenhagen, Universitetsparken 5, DK-2100, Copenhagen, Denmark. bomar@math.ku.dk.
authors.forename: Bo
authors.initials: B
authors.lastname: Markussen
mesh_terms: D000180:Acrylic Resins / Q000494:pharmacology*; D000818:Animals; D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000494:pharmacology*; D050824:Carpal Joints / Q000473:pathology; D006734:Horse Diseases / Q000188:drug therapy*; D006736:Horses; D007270:Injections, Intra-Articular / Q000662:veterinary; D007794:Lameness, Animal / Q000188:drug therapy*; D010003:Osteoarthritis / Q000188:drug therapy / Q000662:veterinary*; D011446:Prospective Studies; D013640:Tarsal Joints / Q000473:pathology; D013997:Time Factors
chemical_list: D000180:Acrylic Resins; D000894:Anti-Inflammatory Agents, Non-Steroidal; C016680:polyacrylamide gels