title: A pendulum test as a tool to evaluate viscous friction parameters in the equine fetlock joint.
abstract: An equine fetlock joint pendulum test was studied and the influence of post mortem time and intra-articular lipid solvent on the viscous frictional response examined. Fresh equine digits (group 1, n=6 controls; group 2, n=6 lipid solvent) were mounted on a pendulum tribometer. Assuming that pendular joint damping could be modelled by a harmonic oscillator fluid damping (HOFD), damping time (τ), viscous damping coefficient (c) and friction coefficient (μ) were monitored for 5h under experimental conditions (400N; 20°C). In all experiments, pendular joint damping was found to follow an exponential decay function (R(2)=0.99714), which confirmed that joint damping was fluid. The evolution of τ, c and μ was found to be significantly (P<0.05) different in the two groups, with a decrease in τ and an increase in c and μ that was faster and more prominent in digits from group 2. It was concluded that pendular joint damping could be modelled by a HOFD model. The influence of post mortem time on results suggested that, ideally, joint mechanical properties should only be tested on fresh cadavers at the same post mortem time. Moreover, the addition of lipid solvent was found to be responsible for upper viscous friction parameters and for a reduced damping time, which suggested that articular lubricating ability was compromised. This equine pendulum test could be used to test the efficacy of various bio-lubricant treatments.
authors.affiliation: Department of Morphology and Pathology, Liège University Faculty of Veterinary Medicine, B-4000 Liège, Belgium. pnoble@ulg.ac.be
authors.forename: Prisca
authors.initials: P
authors.lastname: Noble
authors.forename: Geoffroy
authors.initials: G
authors.lastname: Lumay
authors.forename: Marc
authors.initials: M
authors.lastname: Coninx
authors.forename: Bernard
authors.initials: B
authors.lastname: Collin
authors.forename: Adrien
authors.initials: A
authors.lastname: Magnée
authors.forename: Jacqueline
authors.initials: J
authors.lastname: Lecomte-Beckers
authors.forename: Jean M
authors.initials: JM
authors.lastname: Denoix
authors.forename: Didier
authors.initials: D
authors.lastname: Serteyn
mesh_terms: D000818:Animals; D001696:Biomechanical Phenomena; D002102:Cadaver; D002358:Cartilage, Articular / Q000502:physiology*; D017276:Friction; D006734:Horse Diseases / Q000175:diagnosis; D006736:Horses / Q000502:physiology*; D007596:Joints / Q000502:physiology*; D009991:Oscillometry / Q000379:methods / Q000662:veterinary*; D010808:Physical Examination / Q000379:methods / Q000662:veterinary*; D014783:Viscosity