Page 113 - Barrel Stallion Register 2019

cumulative damage over time. As we look at more of these injuries it seems like many of them are due to a cumulative effect,” he says.
McClure says the meniscus can be injured in one of two ways. “One is acute injury, such as when the horse hangs the leg up, stumbles or falls, or does something causing acute trauma. The other is if the stifle has a subchondral bone cyst or some other problems in the joint that cause arthritis and inflammation. The meniscus can then slowly be degraded by the inflammatory mediators until it becomes weak- ened. Disruption of the cartilage of the distal femur can physically damage the meniscus. This combination of inflammation and physi- cal insult can result in tearing or disruption of the meniscus,” he says. This is a slower onset, secondary to an Osteochondritis Dissicans (OCD) lesion in the distal femur or to chronic arthritic changes in the joint.
In an acute injury, the horse is suddenly lame. It may happen during exertion and sud- den strain on the joint while the horse is being ridden, or out in the pasture when the horse is running around. “With a more gradual prob- lem, the horse will have intermittent lameness issues, and will show positive to a flexion test of the stifle during a physical exam. Radiographs may show evidence of OCD lesions or other arthritic changes that would have been present prior to the meniscal injury,” McClure explains.
DIAGNOSIS
If the horse is lame and the stifle seems
to be the area of concern, it is important to know which part of the joint is affected. “Most horses that have a stifle problem show some swelling of the joint,” says Baxter. “Swelling, particularly in the medial side of the stifle, suggests there is something going on in that joint. Younger horses, particularly cutting horses, barrel horses, or any athletes that do much stopping and turning, may have some extra fluid in the stifles and may not be lame, but we still have to be suspicious that there is something wrong in the joint.
“Early on, some of the problems in the medial femoral tibia joint may not cause true lameness, but they can be performance limit- ing,” he says. “They may not cause much of
a problem unless the horse is trying to do its job.” Athletic activity may cause some pain and discomfort, so the horse won’t do its best or run its fastest, or he might resist doing a certain movement because it hurts.
The stifle joint is one of the more common problem areas in the horse’s rear leg. “Anyone training and working with horses, especially western horses that work a lot off their hind legs, needs to be paying close attention to the size and feel of the stifle,” says Baxter. “They can learn how to feel for heat and swelling in
The meniscus, a fibrocartilaginous pad that fills the space between the distal femur and the tibia, works to help keep everything aligned and stable.
that joint. This is one of the sites that we would thoroughly investigate in any horse with a rear leg lameness.
“Whenever the problem becomes more severe you, will usually find swelling in the joints, and some baseline lameness,” explains Baxter. “The horse will usually respond to flex- ion tests when a person is trying to diagnose this problem.”
Thus, if a stifle injury is suspected,
the veterinarian will do a thorough physi- cal examination and possibly take x-rays
or check the joint with ultrasound. “You can see the medial meniscus and some of the ligaments very well with ultrasound,” says McClure. “Often with an acute medial meniscal injury, the medial collateral liga- ment is also injured. You will be able to see that with ultrasound.
“The most complete diagnostic is often the result of arthroscopy and arthroscopic evaluation of the joint,” he says. “There are also a couple places in this country where they can get a horse’s stifle into an MRI, though this is not very commonly done. Most of the time we diagnose these problems with ultrasound, radiographs and ultimately with arthroscopy.”
TREATMENT
Depending on what the veterinarian finds, treatment may vary. “Some of the meniscal injuries can be debrided, if they are accessible,” says Baxter. “Some of the tears are easily seen with the arthroscope and others are not. Most of the time we try to debride what we can of the meniscus, but it’s not uncommon to have other damage to the cartilage in the joint at the same time. We try to clean it up as best
we can and then the prognosis depends on the amount of damage to the meniscus and articular cartilage.
The most complete diagnosis of a stifle injury is by arthroscopic evaluation of the joint.
A horse with a meniscus injury that comes on gradually will show positive to a flexion test of the stifle during a physical exam.
“What we can actually do depends on what we find,” he explains. “Many veterinarians are treating these joints after the arthroscopic surgery with some of the biological products and regen- erative medicine to speed healing. We know that the meniscus and the cartilage take a long time to heal so we try to speed the healing and have better healing,” he says. Regenerative medicine includes use of stem cells, platelet rich plasma, etc. A lot of these decisions will depend on surgeon preference.
Treatment could vary, depending on the extent of the injury and how badly damaged this structure is. “We’ll usually do arthroscopic evaluation to determine the potential for
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EQUINE HEALTH