Improvements in diagnostics and joint disease management make for better treatment plans.

By Jackie Bellamy-Zions

Prevention is the ideal when it comes to lameness, but practically everyone who has owned horses has dealt with a lay-up due to an unforeseen injury at some point. This article will provide tools to sharpen your eye for detecting lameness, as well as review prevention tips and discuss the importance of early intervention. We’ll begin with a glimpse into current research endeavouring to heal tendon injuries faster, which has obvious benefits to horse welfare and supports horse owners eager to return to their training programs. 

Lameness is a huge focus for Judith Koenig, DVM, DVSc, DACVS of the Ontario Veterinary College (OVC), whose main interest is in tissue healing. She spends half of her time as a surgeon and teacher with a strong interest in Equine Sports Medicine and rehabilitation, and the other half as a researcher at the OVC.

“I think over the past 20 or 30 years we have become very, very good in diagnosing the cause of lameness,” says Koenig. “In the past we had only radiographs and ultrasound as diagnostic tools, but by now most referral centres also have MRI [magnetic resonance imaging] available and that allows us to diagnose joint disease or tendon disease even more. We are much better now finding causes that previously may have been missed with ultrasound.”

Improvements in diagnostics have resulted in increased ability to target treatment plans. With all the different biologics on the market today, Koenig sees a shift in the management of joint disease with people getting away from steroids as a treatment.

Dr. Valverde, professor in anesthesia, Connor McCorkell PhD student, and Emma Chawner DVM at the OVC performing magnetic resonance imaging on a horse in the OVC Health Sciences Centre. Photo courtesy of Ontario Veterinary College

STEM CELL THERAPY

Koenig has investigated the use of many different modalities to see if they accelerate tissue healing and has studied which cellular pathways are affected. When asked about the latest news on research she has been involved in, she proclaims: “I’m most excited about the fact that horses are responding well to stem cell treatment. Better than I have seen any response to any other drug we have tried so far!” 

Two recent collaborative studies have produced very exciting findings, revealing future promise for treating equine osteoarthritis with stem cell therapy. 

In a safety study, Koenig and her team at the OVC have shown equine pooled cryopreserved umbilical cord blood in mesenchymal stem cells (MSCs) to be safe and effective in treatment of osteoarthritis. 

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“These cells are the ones harvested from umbilical cord blood at the time of foaling and then that blood is taken to the lab and the stem cells are isolated out of it,” explains Koenig. The stem cells are then put through a variety of tests to make sure they are free of infectious diseases. Once given a clean bill of health they are expanded and frozen.

The MSCs harvested from multiple donors of equine umbilical cord blood were compared to saline injections in research horses. “This type of cell is much more practical if you have a cell bank,” says Koenig. “You can treat more horses with it and it’s off the shelf.” There were no systemic reactions in the safety study. Research has also shown no different reactions when sourcing from one donor or multiple donors.

In the second study, 10 million stem cells per vial were frozen for use in healing osteoarthritis from fetlock chips in horses that were previously conditioned to be fit. After the fetlock chip was created, exercise commenced for six more weeks and then osteoarthritis was evaluated by MRI for a baseline. Half the horses were treated with the pooled MSCs and the control group received saline before another month of exercise. Then MRI and lameness exams were repeated, as well as arthroscopy to score the cartilage and remove the chip.

Lameness was decreased and cartilage scores were improved in the group that received stem cell therapy at the time of the second look with arthroscopy.

Many diagnostics were utilized during this study. MRIs, X-rays, ultrasounds, and weekly lameness evaluations all revealed that signs of osteoarthritis in fetlock joints improved in the group treated with equine umbilical cord blood MSCs. After six weeks of treatment, the arthroscopic score was significantly lower (better cartilage) in the MSC group compared to the control group.

MRI revealed that the horses treated with stems cells had less progression of osteoarthritis. “They were less lame when exercised after the stem cell therapy than the horses that received saline,” says Koenig. Image courtesy of OVC.

This research group also just completed a clinical trial in client-owned horses diagnosed with fetlock injuries with mild to moderate osteoarthritis changes. The horses were given either 10 million or 20 million stem cells and rechecked three weeks and six weeks after the treatment. Upon re-evaluation, the grade of lameness improved in all the horses by at least one. Only two horses presented a mild transient reaction, which dissipated after 48 hours without any need for antibiotics. The horses’ joints look normal, with any filling (fluid) in the joint reduced.

There was no difference in the 18 horses, with nine given 10 million stem cells and the other nine given 20 million stem cells, so in the next clinical trial 10 million stem cells will be used.

The research team is very happy with the results of this first-of-its-kind trial proving that umbilical cord blood stem cells stopped the progression of osteoarthritis and that the cartilage looked better in the horses that received treatment. 

The future of stem cell therapy is quite promising!

REHABILITATION

It is beneficial for tendon healing to have a certain amount of controlled stimulation. Research has shown that adhering to a veterinary prescribed rehabilitation protocol results in a far better outcome than paddock turnout alone. 

“[These horses] do much better if they follow an exercise program. Of course, it is important not to overdo it.”

Rehab instructions should be carefully followed including hand-walking if prescribed. After time off, horses should be brought back into work gradually and methodically. It takes six weeks to regain muscle strength after injury, but four to six months for bone to develop strength. Photo: Shutterstock/Jaycen

As an example, Koenig cautions against skipping hand-walking if it has been advised. It can be so integral to stimulating healing, as proven in recent clinical trials. “The people that followed the rehab instructions together with the stem cell treatment in our last study — those horses all returned to racing,” says Koenig. “It is super important to follow the rehab instructions when it comes to how long to rest and not to start back too early.”

Related: The Silver Lining of Rehab

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When rehabilitating an injured horse, another concern is administering home remedies that you haven’t discussed with your veterinarian. Examples include blistering an area that is actively healing or applying shockwave therapy to mask pain and then commence exercise.

PREVENTION AND TRAINING TIPS

While stating that there are many methods and opinions when it comes to training horses, Koenig offers a few common subjects backed by research. The first is the importance of daily turnout for young developing horses. 

Cross-training such as trail riding exposes the horse to different types of footing and offers a mental break from intense training. Photo: Clix Photography  

Turnout and Exercise

Many studies have looked at the quality of cartilage in young horses with ample access to turnout versus those without. It has been determined that young horses lacking exercise and kept in stalls have very poor quality cartilage.

Horses started early with light exercise (such as trotting short distances and a bit of hill work) and with access to daily paddock turnout have much better quality of cartilage. Koenig cited research from Dr. Pieter Brama and similar research groups.

Another study shows that muscle and tendon development depend greatly on low-grade exercise in young horses. Evaluations at 18 months of age found that the group with paddock turnout and a little bit of exercise, such as running up and down hills, had better quality cartilage, tendon, and muscle. 

Turn-out from a young age provides lifetime benefits, allowing horses to develop better quality cartilage, tendon, and muscle. Photo: Dreamstime/Olga Itina

Koenig provides a human comparison, with the example of people who recover quicker from injury when they have been active as teenagers and have undergone some beneficial conditioning. The inference can be made that horses developing cardiovascular fitness at a young age gain a lifetime benefit from the early muscle development.

Koenig says it takes six weeks to regain muscle strength after injury, but anywhere from four to six months for bone to develop strength. Horses should be brought back into work gradually and methodically when they have experienced significant time off. The key is regular loading through gradual introduction of exercise.

Rest and Recovery

“Ideally [the horse] has two rest days a week, but one rest day a week as a minimum,” says Koenig. “I cannot stress enough the importance of periods of rest after strenuous work and if you notice any type of filling in the joints after workout, you should definitely rest the horse for a couple of days and apply ice to any structures that are filled or tendons or muscles that are hard.”

Not purporting to be a trainer, Koenig states that two speed workouts a week would be the maximum to allow for proper recovery. In addition, ensure the horse has sufficient access to salt/electrolytes and water after training.

A good period of walking is required in the warm-up and cool down and riders need to pay attention to soundness in the walk before commencing their workout. Check the horse’s legs for heat and swelling before and after every ride and always pick out the feet.

Koenig imparts important advice for bringing horses back into work methodically when they have experienced significant time off. The same precautions can apply to coming back after any lay-up.

Footing and Cross-Training

“Cross-training is very important,” says Koenig. She explains it is critical for the mental and proper musculoskeletal development of the athlete to have a day off for every three training days — or even better, to provide cross-training like trail riding on these days.

Cross-training can mitigate overtraining, giving the body and mind a mental break from intense training. It can increase motivation as well as musculoskeletal strength. Varied loading from training on different terrain at different gaits means bone and muscle will be loaded differently, thus reducing repetitive strain that can cause lameness.

Related: Creating an Equine Fitness Program

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With a European background, Koenig is no stranger to the varying track surfaces used in horses’ training programs. Statistics suggest fewer injuries with horses that are running on turf, as is the practice in the UK. Working on hard track surfaces has been known to increase the chance of injury, but delving into footing is beyond the scope of this article.

Hoof Care

Whether the horse is coming back from injury, or young and beginning training, a proficient farrier is indispensable to ensure proper balance when trimming the feet. Balancing the hoof right from the start is paramount because the horse with some conformational abnormalities, such as abnormal angles, will tend to load one side of their joint or bone more than the other. They will be predisposed to potentially losing bone elasticity on the side they load more because the bone will lay down more calcium on that side in an attempt to make it stronger. This will actually make the bone plate under the cartilage brittle. 

Koenig cannot overstate the importance of excellent hoof care when it comes to joint health, and her strong advice is to invest in a good farrier. Many conformational issues can be averted by involving a skilled farrier starting when the horse is just a foal.

Koenig stresses that prevention truly begins with nutrition of the broodmare before the foal is born. “It starts with how the broodmare is fed to prevent development of orthopedic disease,” says Koenig. Consulting with an equine nutritionist at this stage plays an important role in healthy bone development of the foal, and helping keep the horse sound for a lifetime.

Related: Equine Rehab for the Not-Quite-Right Horse

Related: An Inside Look at Joints

Published with the kind permission of Equine Guelph.

Main Photo: Dreamstime/Donna Kilday