Rumors have circulated in the horse world that administering intrasynovial anesthesia (joint blocks) and intrasynovial medication in the same joint, on the same day, can result in infection within the joint. Chad Zubrod, DVM, MS, Dipl. ACVS, of Oakridge Equine Hospital in Edmond, Okla., recently took a look back at past patients that received intrasynovial blocks, medications, or both. His findings reveal that doubling up on the procedures doesn’t significantly affect the chances of infection. Zubrod presented his research at the 2006 American Association of Equine Practitioners convention in San Antonio, Texas, held Dec. 2-6.

Zubrod found sepsis occurred in one horse out of 500 that received anesthesia alone. Intrasynovial anesthesia and medications were administered to 226 horses, none of which had an infection. Medications included hyaluronan, methylprednisolone acetate, and triamcinolone acetonide. None of the cases had antimicrobials included in their injections. On average, medications were administered 60 minutes after anesthesia.

The results came in via client surveys that asked if horses had displayed any swelling or severe lameness, or required treatment for intrasynovial infection following their injections at Zubrod’s clinic. These results indicate it is unnecessary to delay treatment with intrasynovial medication following a joint block.

However, Zubrod cautioned practitioners about the risk of infection every time a needle enters an intrasynovial space. By increasing the number of times that space is entered, the risk increases as well.

“Every time you put a needle in a joint, there is risk,” Zubrod said. “You have to remember the inherent risk of performing multiple intrasynovial centeses (perforations or tappings) and maintain those aseptic conditions.”

Zubrod also noted local anesthetic potentially delays healing at the intrasynovial injection site and depresses the local immune system within the joint.

Get research and health news from the American Association of Equine Practitioners 2006 Convention in The Horse’s AAEP 2006 Wrap-Up sponsored by OCD Equine. Files are available as free PDF downloads