Tuesdays with Tony
One of the great things about being a cat is that I am admired for simply being. I lay around, I eat, I survey my clinic. My servants would never dream of asking me to fetch things or jump over things. As a cat, I am above that nonsense. But as for the horses that come to my clinic, their people often want them do things. Ridiculous things, like running circles around huge cans of cat food, jumping over sticks they could just as easily have gone around, or prancing around a big litter box with letters on it. It all seems very unnecessary, but you ought to hear the moaning people do if their horse is lame and can’t do those things.
One of the most common things my docs do at Springhill Equine is lameness exams, so let’s talk about what may happen if you bring your horse in for lameness. There are several parts to a lameness exam that help my doc figure out the problem, and you might see my doc doing some or all of these things to check out your horse out. Some types of lameness are more obvious and won’t require all the steps, but for a more subtle lameness, each of them can be a piece in the puzzle to find the source of the problem.
If you drive by my clinic, you will often see horses being trotted up and down the grass outside the clinic while my docs watch them. This is the Springhill technicians’ favorite part of the day. They love the healthy exercise, especially at noon in July and August.
So what does it look like when a horse is lame? It can be an obvious limp in a forelimb lameness. Your horse may not want to bear weight on the leg or may have a pronounced “head bob” when he walks or trots. For a forelimb lameness, think “down on sound” – meaning the head bobs downwards when the sound (non-lame) leg hits the ground. So if the head bobs down when the left front foot hits the ground, the lameness is on the right front leg. For a mild lameness, there may not be a super obvious head bob, especially when he’s moving on a straight line. My doc will also listen to the sound of his footfalls – a lame horse will land softer on the foot that hurts, as he shifts his weight to avoid pain.
Hindlimb lameness is evaluated differently than forelimb lameness. It may look like a “hip hike”, toe dragging, or a shortened stride on the lame hindlimb. It can also just manifest as problems picking up or keeping the canter leads, lack of impulsion, or even “crow hopping” or bucking. Don’t worry if you aren’t sure, that’s what my doc is for. If you’re feeling like something doesn’t seem right, just call my doc.
Some lameness is more subtle than others. If your horse is quite sore, my doc may just need to see him walk and may not need him to trot. For most lameness cases though, the horse is evaluated at the trot, because the symmetrical nature of the normal trot gait makes abnormalities more apparent. Sometimes my doc will ask to see a horse canter to check out how the hind end moves. She will want to see the horse move on a straight line and may want to see him moving in a circle (such as on a longe line) to see how positioning his limbs on the inside or outside of the circle will affect his lameness. Different types of lameness may look worse on soft vs hard ground, so my doc may ask her tech to jog your horse on the asphalt driveway instead or the grass to check out the difference.
Here’s one thing I want you to understand – horses don’t lie about lameness. Their brains don’t work that way. Your horse isn’t “faking” a lameness when you ride him just because he doesn’t look as lame when you see him cantering in the field. He isn’t capable of that. Some things, like the additional weight of carrying a rider, or the specific motions he is asked to do under saddle, just make a lameness more apparent. So if you notice lameness when you ride, just schedule a lameness exam with my doc instead of thinking your horse is being tricksy.
My doc will do an exam to look and feel for abnormalities in the horse’s body. She will look at his conformation and muscle symmetry. She will check out his posture to see if he stands squarely, since abnormal stance can give clues to the areas of discomfort. His hooves and shoes will also be evaluated carefully – I’m sure you have heard the saying “No hoof, no horse” – the angles and health of the hooves are critically important to soundness. My doc will feel your horse’s limbs for heat or swelling and evaluate his tendons for thickening or pain. She’ll feel the limb pulses to look for areas of inflammation. The joints will be palpated for swelling and taken through their range of motion. The exam will often include an evaluation of the back muscles for tension or sensitivity, especially with a hind end lameness.
You may see my doc use a big metal instrument to squeeze your horse’s hoof. That instrument is called a hoof tester and it checks for sensitivity when pressure is applied to certain areas of the hoof. My doc’s knowledge of the anatomy inside the hoof helps her to determine what pain in a certain spot means. Sensitivity in one area may indicate laminitis, whereas another spot may signify a problem with the navicular apparatus. Hooftesters can be used to locate the position of a hoof abscess so my vet can open it up to drain.
You may see my doc holding up your horse’s leg for 30 or 45 seconds and then asking him to immediately trot off – that’s a flexion test. The purpose of a flexion test is to accentuate pain that may be coming from a joint, in order to localize the part of the leg that is bothering your horse or to look for a subtle problem that isn’t immediately apparent. Specific joints are flexed in turn to check the response to that area. If your horse has an arthritic hock, for example, flexing the hock for 45 seconds may make him trot off more lame than he was without the flexion. That can help my doc determine the part of the leg that needs treatment. Flexion tests aren’t always a black or white answer, but they can be a useful puzzle piece in some cases. My doc uses her experience to know the appropriate position, time, and pressure for a flexion test, since it’s possible to get an inaccurate assessment if you flex the joint too hard or for too long. It’s also useful for her to flex the same joint on both the left and right sides to compare how the horse responds.
Nerve or joint blocks
Have you ever gone to the dentist and had a shot to make your tooth numb for a filling? That’s basically the same thing as a nerve block my doc may use during a lameness exam. When my doc “blocks out” an area on your horse’s leg, she is temporarily numbing it to see if that region is the source of the pain. If the correct spot is numbed, your horse won’t look lame anymore since he won’t feel the pain. Unless there is an obvious abnormal finding on her physical exam, my doc will inject a numbing agent into specific anatomical areas until she finds the one that takes away the lameness. Nerve blocks are an injection to directly numb a nerve and the area it supplies feeling to, while joint blocks will inject the numbing agent right into a joint, which is a sterile procedure. Nerve blocks only lasts a couple of hours though, so don’t confuse them for a permanent treatment, they are just a way of finding where the problem is so it can receive the appropriate therapy.
Once my doc has determined which leg your horse is sore on and which part of the leg is the problem, she will often recommend imaging to get a look at what’s going on inside. This is most often an X-ray (radiograph) or ultrasound. Generally speaking, X-rays look at bone and ultrasound looks at soft tissues such as tendons. Occasionally, advanced imaging such as CT or MRI is needed, but the majority of cases can be diagnosed with the imaging equipment at my clinic. Once a specific diagnosis is made, my doc can recommend the best treatment to get your horse sound and back doing those silly things you want to do with him!
Until next week,
P.S. Looking for more information on lameness exams? I bet you can find at least one if not a few podcasts on lameness. Check out our podcast here. You can also search back through my old Tuesdays with Tony to see what wise words I have shared in the past.