Of all the places a horse could develop an infection, a joint is one of the least favorable because it’s difficult to treat and can have catastrophic consequences. Veterinarians commonly treat arthritic joints with injections, and even hands well-practiced in joint injection techniques run into the occasional infection due to bacterial contamination.

Stephen Adams, DVM, MS, Dipl. ACVS, of Purdue University’s School of Veterinary Medicine, recently described how to select and inject drugs to avoid injection, along with ways to recognize and treat joint sepsis at the 2012 American Association of Equine Practitioners’ (AAEP) Convention, held Dec. 1-5 in Anaheim, Calif.

Veterinarians can infuse a variety of drugs into horses’ intrasynovial cavities (joints, bursa, or tendon sheaths). Some medications are more likely to cause sepsis than others; the drug polysulfated glycosaminoglycans (PSGAGs), for example, enhances the infectivity of Staphylococcus aureus introduced via a needle in a synovial cavity.

Yet, Adams explained that if the veterinarian administers the antibiotic amikacin in combination with PSGAGs, he or she can all but eliminate the risk of infection. In a survey of equine practitioners who administer intra-articular injections, 46% said they add antimicrobial drugs to their joint injections and 30% add corticosteroids