Stifle injuries and treatments |

Stifle injuries and treatments

A commonly seen affliction of the stifle is "intermittent upward fixation of the patella" where the joint is locked in the extended position. Photo by Minnesota Veterinary Academy

In the past, an injury to the stifle joint of a horse may have certainly ended his or her career or usefulness. Now, with the ever-evolving science of veterinary medicine, afflictions to the joint have a much higher chance of being treated or even healed.

One of the reasons a stifle injury gives apprehension to horse owners is the complicated nature of the joint said Scott Cammack, D.V.M. He practices at Northern Hills Veterinary Clinic in Sturgis, South Dakota, with several other specialists.

Cammack explains that its treatment is much more involved than similar injuries. For example, an injury to the hock can often be resolved by fusing the bottom two joints (the hock consists of four total). Because it is a low-motion joint, the horse will still be sound and function after fusion.

“The stifle, on the other hand, is a high-motion joint. It’s got a lot of things going on in there. It doesn’t have the capacity to be fused and still be sound. I would consider that they are more serious. They are more prone to long-term issues than a hock is, in my mind,” he said.

According to Dr. Cammack, the stifle is anatomically similar to a human knee. “All the parts are similar to your knee. Just as athletes injure their knees, they injure themselves. They have a patella, they’ve got meniscuses, they’ve got anterior and posterior cruciate ligaments, they’ve got collateral ligaments.” One major difference is that humans have one patellar ligament coming off the kneecap, while horses have three. Therefore, horses can have very unique issues.

One condition, often found in younger horses (aged 2-6) is the “intermittent upward fixation of the patella” or simply a “catchy stifle.” Dr. Cammack describes this condition: “The locking mechanism of the stifle is inappropriately keeping the leg in the locked, extended position. They can’t bend their leg and it only bends at the fetlock. That one is one that we treat in different ways. Sometimes, we’ll do a procedure where we put a needle in the medial patellar ligament and we split it a little bit and cause it to thicken up and tighten up a little bit to help correct that. So that’s a pretty simple procedure.”

Another condition found in younger horses is OCD (osteochondrosis) lesions, a developmental issue. According to Dr. Cammack, they are cyst-like lesions on the bone. “Some of them fill in and some require surgery. We saw one just the other day. A four year old had large cysts up in the bone. All they did was turn the horse out and waited. That one filled in on its own, but that’s not common. Usually you’re injecting the cyst or putting a screw across it or various treatments for something like that.”

On the other hand, older horses may have very different afflictions in the joint. He said, “In my mind, you’re going to see more of the soft tissue injuries in your younger horses and more of the osteoarthritis in the older horses.”

“Older horses are going to be more prone to seeing arthritis in their stifle, which might be secondary to an injury it had had way back when. They injured a collateral ligament and it wasn’t diagnosed, or they have some instability from ligament damage and then it healed some and they got by with it. Years down the road, you’re seeing the arthritis, the osteoarthritis in there.”

Stifle injuries are often seen in performance horses in various disciplines. “When you start getting into any disciplines where they’re having to run hard, turn hard, stop hard, spin. We see it more in the reined cow horses and the reiners and the barrel horses,” Dr. Cammack said. However, injuries can occur on the ranch or in other disciplines, as well. “Certainly any horse can catch some bad ground or find a hole in the ground or something that can cause them injury.”

Interestingly, younger horses may be more prone to injuries that occur in the arena. “We are doing our futurities and so much heavy training on them when they’re young and they don’t have the muscle memory and the skillset to have their leg in the right place at the right time with that amount of force on it.”

Dr. Cammack’s procedure for examining horses includes a flex test, where the joint is stressed momentarily to determine the location of any potential weaknesses in the joints. The end goal is to determine how to optimize the horse’s performance without masking any problems. If the horse deals with chronic issues, the typical injection of HA (hyaluronic acid), a type of steroid, may be administered, costing around $175.

For other injuries, different types of injections may do the trick. “There’s certainly a lot more going on with regenerative medicine than there used to be,” Dr. Cammack said. Using PRP (platelet-rich plasma) can help the joint heal itself. “You’re taking the blood and processing it and pulling out platelet-rich plasma. It’s going to have healing factors and certain proteins that can help the joint get better.” This may cost around $250.

“There’s another one called pro-stride, which is another form of PRP, but it’s a more concentrated form of PRP. It’s more like $450. If you’re getting into stem cells, that goes right up. We just pull the bone marrow or the fat, depending on which form we’re doing and we send it in. With that sample that we send in, we have to send $2,300 to the laboratory. That one can be in excess of $2,500 to do stem cells,” Dr. Cammack said. “It’s an exciting area.”

Cammack has devoted his professional career to the study of equines and particularly their joints and movement.

“When I was in college, I started working at this clinic with Dr. Margie Jones. I developed a strong affinity for equine work and did a year internship with an equine surgeon in California, but he did a sports medicine practice and then I got in the deep pool of sports medicine and developed a deep love for it,” he said.

More severe injuries to the stifle may involve surgeries, which range vastly in involvement and price.

This article serves as a brief overview of a very large field of veterinary study. Dr. Cammack devotes much of his practice and time to learning more about the equine, attending the yearly American Association of Equine Practitioners conferences, and expanding into regenerative medicine.