With the growing arsenal of intra-articular (IA) and biologic therapies available, however, what are some of the easiest-to-use and most cost-effective options for the ambulatory vet? Hand reviewed traditional joint therapies veterinarians can find on their shelves during his presentation at the 2022 American Association of Equine Practitioners (AAEP) Convention, held Nov. 18-22, in San Antonio Texas.

Corticosteroids and Hyaluronic Acid

Hand focused his talk on the most common IA medications used to treat equine joints affected by osteoarthritis or synovitis (inflammation of the joint lining): hyaluronic acid (HA) and corticosteroids. The latter group includes the following:

• Triamcinolone acetonide (TCA) is the most commonly used corticosteroid for high-motion joint (i.e., fetlock) injections, according to a 2020 survey of AAEP members. While it poses no risk to healthy horses, Hand cautioned against administering it to laminitis-prone metabolic horses.
• Methylprednisolone acetate (MPA) is the most common injectable corticosteroid for low-motion joints (i.e., the pastern and lower hock), according to the AAEP survey.
• Betamethasone esters (BME) is the third-most common option for either joint type.

Hand noted that many of the survey respondents include the antibiotic amikacin when injecting joints but cautioned against its use, because research has shown it can cause cartilage damage.

Veterinarians often administer HA or polysulfated glycosaminoglycan (PSGAG) in conjunction with corticosteroids. Which product they choose depends on cost, availability, veterinarian preference, and molecular weight, said Hand. High-motion joints, for example, might warrant a higher molecular weight option to reduce friction.

“Overall, the use of corticosteroids is very economical,” he said. “Even with the combination of HA or PSGAGs, the costs are within most client’s budgets to treat their horses.”

While traditional IA therapies make injecting joints at clients’ farms safe, easy, and cost-effective, Hand noted these procedures do require different considerations than injections at the clinic. One of those is environmental; sterility becomes a factor when performing injections in a grooming or wash stall or on a horse that’s just come in from pasture, said Hand.

“Due to these field conditions, many clinicians will often add antibiotics to injections” to prevent infection, he said. Joint sepsis, however, remains rare.

Take-Home Message

Many promising biologic joint injectables require special processing or storage, making them impractical for field use, said Hand. For this reason, he added, traditional off-the-shelf therapies such as corticosteroids and HA remain appealing for ambulatory practitioners looking to manage their patients’ joint pain.

“When guidelines are followed, traditional joint therapies are very economical, readily available, and successful for the management of joint conditions in the field,” he said.