Accurate diagnosis is critical

By WCVM Today

A lame horse often means a sudden change in plans, and a lameness diagnosis during the summer is an especially disappointing way to end the show season for a horse and its rider. 

In addition to conventional lameness therapies, newer treatments such as shock wave therapy, cold compression therapy, and regenerative therapies that use the body’s natural ability to heal may help to return horses to the show ring more quickly. 

But what’s even more critical than choosing the best therapy is diagnosing a horse’s lameness as soon as possible to avoid complications, says Dr. Kate Robinson of the Western College of Veterinary Medicine (WCVM).

“There are many diseases responsible for causing lameness,” says Robinson, an assistant professor of equine field service at the veterinary college. “A thorough diagnosis allows us to come up with the most appropriate treatment plan for the horse.”

Close Ups of an equine foot. Photos: Christina Weese

Common Lameness Issues

Here are some of the most common lameness issues that Robinson and her WCVM colleagues see in their equine patients:

Caudal heel pain

Also known as navicular disease or syndrome, caudal heel pain commonly affects the front feet of Quarter Horses and warmblood horses, but can affect any breed of horse. It is rarely found in the hind feet.

“We prefer to call it caudal (or palmar) heel pain, because as we’ve learned more about the disease, we’ve become aware that it’s not just the navicular bone’s fault. The soft tissues in the heel region cause pain,” says Robinson. 

Horses with caudal heel pain often have a short, choppy stride and appear lame from the shoulder because they’re reluctant to move the sore foot forward.

Osteoarthritis (OA)

This degenerative joint disease, more commonly known as arthritis, is a chronic breakdown of the cartilage in the joint. The low hock joints and coffin joints are commonly affected by arthritis. Even the horse’s stifle joint can become arthritic.

Arthritis may be caused by general wear and tear on the horse’s joints, or by faulty conformation. It can also be a secondary problem caused by another disease such as synovitis or osteochondritis dissecans (OCD).

“A horse with an injured joint is more at risk of developing arthritis,” says Robinson.

Osteochondritis dissecans (OCD)

OCD is a developmental disease that can affect any breed of horse but is more common in young warmbloods, thoroughbreds, and Arabians. OCD causes the cartilage and bone to form improperly. 

“We see little fragments within the joint because of the malformations of cartilage. It’s not a fracture, but it’s an abnormal ossification of the cartilage and bone,” says Robinson. 

Horses affected by OCD aren’t necessarily lame, but their owners may see significant swelling of joints and lameness during and after workouts.

Bowed tendon

Tendonitis of the superficial flexor tendon, located on the back of the limb, is commonly caused by trauma. Another potential risk factor is age – older horses can develop bowed tendons. Depending on the degree of injury, the lameness can be quite mild or quite severe.

Desmitis

Desmitis is inflammation and injury to a horse’s ligament. It may be traumatically induced or it can be a wear-and-tear problem based on what the horse does for a living, says Robinson. The list of most commonly injured ligaments includes the suspensory ligament, the collateral ligament(s) of the coffin joint, the accessory check ligament(s), and the distal sesamoidean ligament(s).

Therapy Options

Before implementing a treatment plan, veterinarians use various tools including palpation, lameness evaluation, flexion tests, nerve and joint blocks, and diagnostic imaging such as X-rays, ultrasound or MRIs (magnetic resonance imaging) to diagnose lameness.

An equine standing MRI is an option for diagnosing subtle lamenesses. Photo: Christina Weese

Conventional therapies are still commonly recommended to treat horses’ lameness issues.

“[These include] rest, cold therapy in the form of cold hosing, and nonsteroidal anti-inflammatory drugs (NSAIDs) such as Bute® [phenylbutazone] or Banamine® [flunixin meglumine],” says Robinson. “More often than not, we are going to use our tried–and-true Bute® because it works well for musculoskeletal problems. Steroid joint injections are also commonly done for problems like arthritis or OCD.”

As part of a lameness exam, WCVM equine surgeon Dr. Joe Bracamonte performs a flexion test on a horse (above), and trots the horse down the paved runway (below) of the college’s equine performance centre. Photo: Christina Weese

Robinson adds that hyaluronic acid (HA) is commonly injected into a horse’s joint because it is a natural component of the joint fluid, and it helps to put more of the natural “good stuff” back into the diseased joint. As well, HA has anti-inflammatory properties and can help with inflammation in the joint. 

While Robinson sees no fault in using conventional therapies, some of the newer lameness treatments may help a horse recover from a lameness issue more quickly.

Game Ready®

This is an advanced therapy option that relies on a conventional method — cold compression — to treat a lameness. “The big advantage with Game Ready® is that the horse stays dry — unlike cold hosing. We can treat multiple legs or areas at once with the split hose,” says Robinson. 

WCVM veterinarian Dr. Katherine Robinson (right) lets a young rider experience the effects of a Game Ready® wrap on her arm. Photo: Christina Weese

Veterinarians use Game Ready® to treat inflammatory problems such as acute tendonitis and desmitis. The wrap is applied to the affected area and then a hose circulates ice water through the wrap. Water pressure, temperature, and application time can be preset to fit the needs of an individual horse.

A close up of the Game Ready® wrap on a horse's limb. Photo: Christina Weese

Robinson recommends treating the horse once a day for three to five days with Game Ready®, but she adds that it depends on the reason for treatment and the horse’s response to the treatment.

Shock wave therapy

Shock wave therapy is also referred to as extracorporeal shock wave therapy (ESWT) — but Robinson wants clients to know that the therapy doesn’t use an electric shock. 

“It’s a high-pressure wave that’s sent through the tissue by a trode (probe),” she says. “Shock wave therapy is the opposite of Game Ready® because we use it to treat chronic conditions like arthritis and caudal heel pain.”

Shock wave therapy stimulates the cells to produce growth factors and other proteins that help with healing. It helps initiate an anti-inflammatory response and helps blood circulation by encouraging new blood vessels to form.

Equine field service veterinarian Dr. Anne Marie Guillemaud conducts an ultrasound examination on a horse’s lower limb during a public demonstration. Photo: Christina Weese

Since the shock waves travel like ultrasound waves, veterinarians prepare the treatment area just as they do before an ultrasound examination. If necessary, they will clip the hair and apply some alcohol to the area. Then they will apply ultrasound gel so the shock waves can better penetrate the tissues and to minimize discomfort for the horse.

“Typically we recommend between one to three treatments done at two-week intervals, but it depends on the problem and how well the horse responds to the treatment,” says Robinson.

Interleukin-1 receptor antagonist protein or IRAP®

IRAP® is an anti-inflammatory product that clinical teams can create from the horse’s own blood. It’s also referred to as autologous conditioned serum (ACS). 

First, a veterinarian takes a small amount of the horse’s blood and transfers it to a sterile container with glass beads. Next, the blood is incubated for 20 to 24 hours before it’s placed in a centrifuge to separate the cells. Finally, the horse’s serum is injected back into its own joint.

Robinson describes IRAP® as the “good guy” because it binds to interleukin 1 (IL-1) — an inflammatory protein that’s commonly found in arthritic joints — and prevents IL-1 from causing more inflammation within the affected joint.

Robinson says treatment with IRAP® yields different results for each horse, but it’s been a success in treating arthritis.

Platelet-rich plasma (PRP)

Another regenerative product that’s created from the horse’s own blood, veterinarians create PRP by drawing a very small amount of the horse’s blood with a specialized syringe. The collected blood is then added to a centrifuge before it’s inserted back into the area requiring treatment.

“It’s rich in growth factors, so it helps with healing. It essentially ‘revs up’ the healing and repair process,” explains Robinson. “But it’s tough to compare from horse to horse and it’s difficult to predict how it’s going to work because it’s a very individualized product [created] from an individual animal.”

Soft tissue injuries such as tendonitis and desmitis are treated with PRP, so Robinson prefers to use ultrasound guidance to treat the right spot. As with IRAP®, the treatment protocols with PRP do vary depending on the clinician’s preference, the horse’s injury, and how they respond to treatment.

But before trying any treatment — old or new — Robinson emphasizes how critical it is to diagnose the problem before it gets worse.

“We want to come up with a definitive diagnosis based on clinical signs,” she says. “We want to really know what’s going on before we begin any treatment.”

Main Photo: ©CanStockPhoto/Labrador