Flexion Test Noltrex Joint Lubricant for Horses

Noltrex®Vet Histological Study Design & Results

Principal Investigator: Dr. Scott McClure, DVM, PhD, Dipl. ACVS

Clinical and Histologic Evaluation of Polyacrylamide Gel in Normal Equine Metacarpal /Metatarsal-Phalangeal Joints

Mcclure, S. R., Yaeger, M., & Wang, C. (2017). Clinical and Histologic Evaluation of Polyacrylamide Gel in Normal Equine Metacarpal /Metatarsal-Phalangeal Joints. Journal of Equine Veterinary Science,54, 70-77. doi:10.1016/j.jevs.2016.11.016

NoltrexVet - Clinical and Histological Study Noltrex Polyacrylamide Gel in Horses

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This is an IACUC approved, controlled study to evaluate the clinical, histologic and metabolic effects of polyacrylamide gel in normal fetlock joints.

24 fetlocks from 6 horses were treated with Noltrex®Vet prior to evaluation at day 7, 28 and 56.

Synovial fluid was collected prior to administration of polyacrylamide hydrogel and again at the completion of the study for cellular, fluid, and biomarker evaluation.

At the completion of the study, gross examination, and cartilage and synovial membrane histology were performed.


Polyacrylamide was clearly visible on the surface of the synovium at 7 days post-injection, and more material appeared in the interstitial spaces of the synovial membrane at days 28 and 56.

There was a small by significant (p = 0.0242) increase in nucleated cells within the synovial fluid 7 days after the administration of polyacrylamide, which normalized on days 28 and 56.

There was an absence of inflammatory reaction in the synovial membrane post-injection, as demonstrated by no observable change in cellular infiltrate by microscopy.

All horses remained sound through the study, as demonstrated by flexion tests.

Conclusion: There was no evidence of any detrimental histologic or metabolic effects and the horses remained sound throughout the study period.

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