The objective of joint therapy is to decrease pain using an osteoarthritic drug that modifies clinical signs and to minimize further deterioration with a disease-modifying osteoarthritic drug. At the 2008 American Association of Equine Practitioners convention, held Dec. 6-10 in San Diego, Calif., David Frisbie, DVM, PhD, Dipl. ACVIM, of Colorado State University's Equine Orthopaedic Research Center, compared the use of polysulfated glycosaminoglycans (PSGAGs) and sodium hyaluronate (HA) in arthritic carpal (knee) joints.

Frisbie urged practitioners to make an accurate diagnosis, assess the clinical severity, and allow an appropriate rest period when implementing a therapeutic plan. Decision for drug therapy must also consider economic limitations and the possible side effects. Currently, there are many therapeutic choices, ranging from non-steroidal anti-inflammatory drugs, corticosteroids, PSGAGs, and HA, to novel biologics such as interleukin-1 receptor antagonist protein (IRAP)–also called autologous conditioned serum (ACS).

Historical studies have demonstrated that either PSGAGs or HA significantly reduce lameness over five to seven weeks following administration of multiple doses. In his presentation Frisbie reviewed treatment using either PSGAGs or HA directly injected into knee joints at two, three, and four weeks following an arthroscopically induced chip fragment in each joint. A control group of horses received saline injections at the same intervals for comparison. The 24 study horses were then exercised five days per week until Day 70. Investigators collected synovial fluid weekly for analysis, along with performing sequential musculoskeletal exams, radiographs, and MRI studies