Rheological Study of a Novel Viscosupplement

Abstract

Osteoarthritis is a widespread joint disease that causes joint paint, stiffness, and loss of mobility. Over 10% of adults suffer from knee osteoarthritis alone. Despite the prevalence of the disease, there is a lack of effective treatments for osteoarthritis and consequently the disease progresses over time to the point of causing disability.  
As osteoarthritis progresses, synovial fluid loses inherent viscoelastic properties that make it an effective lubricant and shock absorber for weight bearing joints. The composition of synovial fluid constituents is observed to change as the disease progresses and is attributed as the primary reason for the change in fluid behaviour. In particular, hyaluronic acid concentration and molecular weight are observed to decrease.
The principle behind viscosupplementation, a treatment for osteoarthritis, is to replace disease altered synovial fluid with a synthetic fluid comprised of high molecular weight and concentration hyaluronic acid via an intra-articular injection in order to restore natural shock absorbing and lubricating properties to the joint.
The current work studies the shear and viscoelastic properties of a set of novel hyaluronic acid derivatives and aims to evaluate their suitability as a treatment for osteoarthritis based on rheological properties and comparison to existing viscosupplements. The compounds also possess anti-inflammatory properties which may further improve the diseased state of an affected joint.
Parameters of interest include degree of shear thinning, zero shear viscosity, crossover frequency and time dependent behaviour. These parameters will be compared to existing viscosupplements as part of the treatment evaluation.