The Horse:Your Guide To Equine Health Care provides monthly equine health care information to horse owners, breeders, veterinarians, barn/farm managers, trainer/riding instructors, and others involved in the hands-on care of the horse.
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31 February 2016 THE HORSE TheHorse.com Goodrich said it's crucial to take steroid administration seriously, administer- ing these drugs only when needed. She described one study of 1,911 horses, 392 of which had received intra-articular (IA) corticosteroids. The researchers found a positive association between corticoste- roid administration and subsequent mus- culoskeletal injury; in other words, horses that had IA corticosteroid injections could be more likely to sustain an injury. Hyaluronic Acid (HA) This is naturally found in horses' synovial (joint) fluid, and veterinarians can also apply it with the goal of decreasing synovitis, a less-dam- aging type of joint inflammation. Debate exists over whether high- or low-molecular-weight HA is more benefi- cial for use in horses' joints. Essentially, high-molecular-weight HA contains larger molecules than low-molecular-weight. Goodrich said the commercially avail- able intravenous HA product (marketed as Legend) is effective at decreasing joint inflammation in many horses. Corticosteroids + HA Goodrich said there's not much research to indicate that a combination of these two treatments is better than one alone. In fact, she added, researchers had better results in one study when they used triamcinolone alone than with HA. In another study, administering HA with methylpredniso- lone did not decrease the corticosteroid's detrimental effects on cartilage. Polysulfated glycosaminoglycan (PSGAG) Goodrich said early literature showed that intra-articular PSGAG (mar- keted as Adequan) consistently helped re- duce synovial effusion (swelling) and joint capsule fibrosis (scarring). But, she noted, there is a risk of joint infection due to its administration route. Many practitioners opt to use the intramuscular formula, which poses a lower risk of infection, but could be less effective in improving joint problems, she said. Polyglycan This is made up of hyal- uronic acid, chondroitin sulfate, and N-acetyl-D-glucosamine. It's labeled for IA post-surgical lavage and replacement of synovial fluid, but it is not currently marketed or approved as a drug in the United States. Still, many practitioners have found this "device" useful to reduce lameness and increase bone proliferation in ailing joints, Goodrich said. Polyglycan appears most useful in horses that still have full-thickness cartilage, she added. Goodrich stressed that veterinarians should not administer polyglycan intra- venously, as it could have detrimental effects. Pentosan polysulfate This injectable product (marketed as Pentosan), which Goodrich said has been used in Australia and New Zealand for 20 years, is similar to HA, and good anecdotal reports back its use. It is thought to decrease cartilage fibrillation (softening and grooving of joint surface cartilage) and improve carti- lage histology (cell makeup), making it a very promising treatment option, she said. Goodrich said in one unpublished study researchers found that horses receiving pentosan polysulfate appeared to respond to treat- ment faster than those receiving PSGAG, and the PSGAG horses returned to their pre-treatment state sooner than those receiving pentosan polysulfate. It is not approved for use in the United States. Diclofenac sodium Goodrich said she prefers to use this topical NSAID (mar- keted as Surpass) as an adjunct to other internal joint treatments. Firocoxib This relatively new non- steroidal (marketed as Equioxx) has a similar pain-reducing effect as phenyl- butazone (Bute), Goodrich said. It is less likely to cause gastric ulcers, however, a common side effect of Bute. Indeed, there are equine joint treat- ments galore. Your veterinarian can help determine which option is suited for your horse's situation to give him the best chance of returning to soundness or remaining sound. Are Ossified Ungular Cartilages Clinically Significant? Horses have some special cartilages— yes, like the tough, flexible tissue that makes up your nose—on either side of the coffin bone in each foot. They're thought to aid in shock absorption, support of the Flunixin vs. Firocoxib After Colic Surgery After your horse undergoes colic surgery, he'll likely receive medication to reduce inflam- mation and relieve pain associated with the procedure. But does it matter which anti- inflammatory the veterinarian reaches for to keep your horse comfortable? Prof. Kerstin Fey, Dr. Med. Vet., Dipl. ECEIM, an equine internal medicine specialist at the Justus Liebig University, in Giessen, Germany, worked with Julia Wiegand, DVM, to study this topic. Fey said veterinarians often use non-steroidal anti-inflammatory drugs (NSAIDs) following colic surgery, but there are only a few studies evaluating their effects on horses' pain levels and no comparative studies after colic surgery, she said. So Fey, Wiegand, and colleagues compared how well two commonly used NSAIDs— flunixin meglumine (Banamine) and firocoxib (Equioxx)—accomplished this. They studied horses of mixed breeds and ages admitted to a German equine veteri- nary clinic for colic surgery from December 2012 through February 2014. They excluded broodmares in late gestation, very young horses, and horses with long surgical durations, extended recovery times, and additional complications. One study group received firocoxib, while the other received flunixin before general an- esthesia and six, 12, 20, and 32 hours after surgery. Trained personnel used a pain scoring system based on behavioral and clinical parameters. Ultimately, the team found no significant differences in how firocoxib and flunixin relieved pain following surgery, and both drugs reduced horses' pain scores similarly with a "remarkable reduction in the first 12 hours after surgery," Fey said. She noted that the study was not blinded and there was no placebo control group to which they compared the drugs' efficacy for ethical reasons, and that additional studies on pain score data are needed in the future.—Erica Larson Horses with ossifed ungular cartilages could be at risk of developing lameness. COURTESY DR. SUE DYSON