WCVM team researches septic arthritis

Joint fluid was removed from horses to investigate the levels of SAA protein, a possible marker of septic arthritis. Photos: Dr. Joe Bracamonte. 

Dr. Andres Sanchez of the Western College of Veterinary Medicine (WCVM) hopes to prove that a protein called serum amyloid A is a valuable tool for monitoring the healing progress while treating septic arthritis in horses.

Besides the skills he has gained as a large animal surgical resident and researcher over the past few years, Sanchez has learned a thing or two about training horses — mainly from a horseman he worked with in Argentina.

“He taught me to treat each horse differently and gain their confidence and trust,” says Sanchez as we get acquainted with the horses involved in this summer’s project — the next phase of his SAA research.

At first, I doubt that we will ever be able to catch some of these horses that are very skittish about being haltered. But my doubts vanish after the first few days, and I try to learn as much as I can from Sanchez for any challenging patients in my future work as a veterinarian.

In addition to horsemanship skills, I’ve learned a lot about serum amyloid A (SAA) from Sanchez. This protein is present in the blood and in joint fluid, and has been shown to increase during cases of joint infections (also known as septic arthritis) in horses. Measuring SAA levels may prove to be a valuable tool for equine practitioners when treating infected joints — a condition that can be devastating for horses.

In 2013 Sanchez and his supervisor, WCVM equine surgeon Dr. Joe Bracamonte, examined the response of SAA levels to arthroscopic lavage of joints. This is a common treatment method for joint infections that involves flushing the joint with fluid using a camera-guided scope.

When the two researchers performed the arthroscopic lavage procedure on the horses in the study, the markers generally used to assess septic arthritis increased, but SAA levels remained the same. This meant that SAA was specific to the infection itself and wasn’t influenced by the arthroscopic treatment – suggesting that SAA is an ideal marker.

This summer, I’m working with Sanchez and Bracamonte on the next phase of the research project that’s supported by the college’s Equine Health Research Fund (EHRF).

In this phase, we’re performing repeated “through-and-through” needle lavage of horses’ hocks. This technique involves placing two needles in a horse’s hock joint and flushing it with fluid using a pump.

Through-and-through lavage is often used as an alternative treatment option to arthroscopy or used in combination with it since it’s an effective procedure.

“We want to validate SAA as an accurate marker that is not affected by procedures that are used to treat septic arthritis,” says Sanchez.

Research aims to determine if SAA levels can be used to assess “through-and-through” lavage — a less expensive procedure than arthroscopic lavage. 

After each procedure, we monitor the levels of SAA and other markers commonly used to evaluate septic joints.

If SAA proves to be a specific marker for septic arthritis that isn’t altered by treatment procedures like the through-and-through option, the benefits will be numerous.

“This will provide a better way to monitor treatment and the progression of disease,” says Sanchez.

By creating more targeted treatment plans based on SAA levels, veterinarians can avoid potentially aggressive treatment options that cause a lot of stress for their patients.

Referral cases will also reap the benefits of SAA monitoring. Horses that are referred to specialized veterinary hospitals such as the WCVM Veterinary Medical Centre have often received previous treatments for joint infections by the referring veterinarian. Research has shown that these treatments increase the markers commonly used to assess septic arthritis and can make it difficult to monitor the disease.

SAA would be extremely useful in these cases, giving equine practitioners a better understanding of the disease’s progression.

As a next step, Sanchez plans on continuing his research by looking specifically at the SAA that’s synthesized by the synovium — the thin layer of tissue that lines the joint.

“Each project that we do is a glance into the unknown and unexpected. That is what I love about research,” says Sanchez.

I’ve enjoyed the research, too — plus I’ve also appreciated learning more about handling horses. The morning finally comes when I’m alone with the most challenging horse to halter in the herd — a small chestnut mare with a delicate star between her eyes.

I try to remember everything Sanchez did while we worked together with the horses. Before I know it, I’ve haltered the mare!

Now the day’s research can begin.

Lea Riddell of Winnipeg, Man., is a third-year veterinary student who was part of the WCVM’s Undergraduate Summer Research and Leadership program in 2014. Lea’s story is part of a series of articles written by WCVM summer research students.