Hydrotherapy for a Horse Points to Skeletal Solution
Napoleon In Water Treadmill
Dr. Jamie Kopper and fourth-year student Heather Murphy support Napoleon during his first hydrotherapy.

Horses born with severely underdeveloped bones face an uphill battle that usually ends in one of two ways: severe juvenile arthritis or euthanasia. A new rehabilitation-based protocol may be the first step toward giving these youngsters a renewed chance at quality of life.

When horses are born with incomplete ossification, the bones in their legs did not fully develop during gestation. Foals, who are athletes by nature, run the risk of crushing these bones when they run and play. The damage can result in juvenile arthritis, which causes severe pain and lameness.

“It’s just no way to live,” said Dr. Elizabeth Carr. “It can be extremely difficult to manage, which leaves the horse and owner without a lot of options.”

Dr. Carr is working to change that. She’s the head of large animal clinical services and the associate director at the MSU Veterinary Medical Center. With the help of Dr. Sarah Shull and the Hospital’s Rehabilitation Service, she’s exploring new ways to treat severe cases of incomplete ossification that will minimize damage to these developing bones while allowing the foal to be active and gain muscle and ligament strength.

“Once the horse is born, the first step is to try to allow the bones to develop as much as possible while limiting weight-bearing and crush,” said Dr. Carr. “Because foals naturally want to run and play it can be difficult to limit exercise once they are healthy.  This is where rehabilitation techniques become very helpful. 

Dr. Carr and her team first treated a filly with a mild form of incomplete ossification and achieved good results. The second foal to experience this new approach was Napoleon, a newborn colt who made a remarkable recovery. Napoleon’s mother had an infected placenta. This created a poor environment for Napoleon’s development.  He was born before he was fully developed and was sick and much smaller than a normal foal.  Because he was underdeveloped, or dysmature, his tarsal and carpal bones—the small bones in his hock and knee—were not fully developed.

“He was also septic when he arrived here at MSU,” said Dr. Jamie Kopper, large animal resident. “His owners got him here right away, so we were able to quickly intervene, and luckily he did not go on to develop septic joints or other catastrophic complications.”

Septic joints would have given Napoleon an even worse prognosis, but it was still no cake walk. He was diagnosed with stage one incomplete ossification. Out of the four stages, stage one is the most severe.

“We couldn’t even see all his bones on radiographs,” said Dr. Kopper. “Where he should’ve had developed bones, there was nothing but cartilage.”

Napoleon was placed on bed rest while he was treated with antibiotics, fluids, and IV nutrition. He was not allowed to move on his own, and could only stand up with the help of the MSU team. After three weeks, the team fit Napoleon with two casts for his fore limbs. The casts protected Napoleon’s developing bones while allowing him to stand and lay down on his own.

“The casts allowed him to continue to form the missing bones,” said Dr. Carr. “The downside of using casts is that they don’t allow the patient to strengthen their ligaments and tendons. That’s why we moved to hydrotherapy.”

Hydrotherapy involves the use of an underwater treadmill. It’s commonly used for dogs and cats to help manage medical conditions and rehabilitate after surgeries. A colt was something new.

“To our knowledge, it’s never been done before,” said Dr. Carr. “But our small animal patients have had so much success with hydrotherapy that we decided the potential rewards outweighed the risks for Napoleon.”

The underwater treadmill allows the team to support part of Napoleon’s weight with the water while still allowing him to stand and walk and begin to strengthen the muscles and ligaments in his limbs.

“The underwater treadmill is a great tool because it allows us to restore and build a baseline of fitness for our patients,” said Dr. Shull. “It provides access to strength training with a minimal risk of new injury or further damage.”

Napoleon started out walking on the water treadmill for 30 minutes per day, 5 days per week. After a week and a half, he was almost at a full trot.

“His progress is really indicative of a successful outcome,” said Dr. Kopper. “The fact that he went home alive and without any current orthopedic damage is a huge success. He has more than beaten the odds just by getting this far.”  The other filly also was treated with underwater treadmill exercise.  At her four-month recheck her bones were completely formed with no evidence of crushing injury or osteoarthritis.

Because of Napoleon’s results, Dr. Carr plans to use the underwater treadmill on future cases to see if the team can improve the prognosis for other foals.

“The goal is to design a protocol that will allow us to determine the most effective use of hydrotherapy for patients with incomplete ossification,” said Dr. Carr. “So far, the short-term results are promising.  If this technique can help prevent the development of crippling arthritis, there are a lot of lives to be saved.”