Transcript:

[0:00]

Hi everyone, welcome back to Mad Barn Academy, and if you are new here today, then welcome — we hope to earn your subscription. I’m Dr. Fran Row, one of the veterinary nutritionists here at Mad Barn, and today’s topic is going to be on lameness examination. Lameness is one of the most common reasons owners call their vets, both in emergency and non-emergency situations, so I wanted to go through the process of a lameness workup so that you can know what to expect the next time you set up an appointment with your vet to deal with some type of lameness.

[0:41]

Let’s start by defining what lameness actually is. Basically, lameness is an abnormal gait or stance that results from a dysfunction of the locomotor system. In horses, the most common dysfunction is some type of musculoskeletal pain; however, lameness can also result from neurological or mechanical dysfunction, though generally less frequently. Lameness is one of the most costly health issues in the equine industry, both in terms of the cost of diagnosis and treatment, but also the cost associated with loss of use — whether that be temporarily while the horse is healing and recovering, or potentially indefinitely if it’s something severe enough. Lameness can affect all types of horses, of all ages, and of all disciplines, so it’s definitely an issue that many horse owners are familiar with — whether or not we want to be.

[1:52]

The goal of a lameness exam is to figure out what the inciting cause of that lameness is so that we can treat it appropriately. Sometimes it’s really obvious — the horse is limping, there’s a wound, there’s swelling, etc. In other cases, it’s not so obvious — the lameness may be mild, inconsistent, or it just presents as a performance issue, and we don’t initially realize that it’s a true lameness resulting from pain or another issue. The lameness exam is a methodical process that helps the vet determine where the lameness is coming from and what structures are involved.

[2:51]

We can break down this exam into three big categories: recognition — determining which limb or limbs are the source of the lameness; localization — isolating the lameness to a particular region of the limb; and resolution — developing an appropriate treatment plan to address that lameness. In the majority of cases, your vet will follow this step-by-step process to isolate the lameness. Not all steps are necessary in every case, but this gives you an idea of what to expect with the normal progression of an appointment and lameness workup. Let’s go through each step in more detail.

[3:50]

Our first goal is to determine which limb or limbs are the source of the lameness — recognition. Your vet will start by gathering a history, asking you questions to get background on what’s been going on: When did you first notice the lameness? Has it gotten better, worse, or stayed the same? Have you tried treating it? Does the horse have a history of lameness, old injuries, arthritis, or laminitis?

[4:38]

Next is a physical exam, looking at and palpating the horse while it’s standing at rest. As your vet approaches, they’ll assess how the horse is standing and look for obvious abnormalities such as swelling or wounds. If nothing is apparent from afar, they’ll do a hands-on palpation of the neck, back, and all limbs, apply hoof testers to all four feet to check for sensitivity, pick up the limbs to assess passive range of motion, and feel for heat, pain, swelling, reduced range of motion, sensitivity to hoof testers, or increased digital pulses — anything that could point toward the source of lameness.

[5:58]

Next, the vet will watch your horse go. If the horse is severely lame, they’ll skip the motion exam to avoid further injury. In most other cases, the motion exam helps determine or confirm which limb is affected and how severe the lameness is. They’ll recreate the circumstances in which the lameness becomes evident — trotting in hand on a straight line on both hard and soft surfaces, trotting in a circle (lunging or round pen), and sometimes watching the horse under saddle or in harness.

[7:11]

A front limb lameness is generally identified by a head nod — “down on the sound,” meaning the horse’s head goes down when the non-lame limb is on the ground. Hind limb lameness is often seen as a hip hike, but stride length, arc of limb flight, drifting, and tail carriage can also help identify it. The vet will also listen for evenness of footfall, particularly on hard surfaces — a sound horse has even, symmetrical footfalls; a lame horse will have an asymmetrical sound.

[8:18]

To characterize the severity of lameness, vets use the American Association of Equine Practitioners (AAEP) lameness scale, graded 0–5. Grade 0 means no lameness. Grade 1 is mild and difficult to observe, not consistently apparent. Grade 2 is difficult to observe at the walk or trotting in a straight line, but becomes apparent under certain conditions like weight-carrying, circling, inclines, or hard surfaces. Grade 3 is consistently observable at the trot under all circumstances. Grade 4 is observable at the walk. Grade 5 is the most severe — minimal or non-weight-bearing in motion, or non-weight-bearing at rest, or unwilling to move.

[10:31]

Now that we’ve determined which leg is the problem, the next goal is to isolate the lameness to a particular region of the limb — localization. After watching the horse go in hand, your vet may perform flexion tests or limb manipulation tests. They’ll hold the limb in a flexed or extended position for 30–60 seconds, depending on the region, then have the horse trot off immediately. Usually, the vet or helper will count down from “5, 4, 3, 2, 1 — trot!” so the handler knows when to move as soon as the limb is released. Your vet may perform lower and upper limb flexions on all four limbs, as well as stifle extension or stifle crossover manipulations.

[11:45]

Lower limb flexions are meant to stress the fetlock down — so the fetlock and the digit. Upper limb flexions are meant to stress the joints above the fetlock. In the front leg, that’s going to be your knee and your elbow; and for the hind limb, that’s going to be the hock, stifle, and hip. Stifle extension, or that crossover, is meant to stress the stifle more specifically.

[12:09]

Now, flexions aren’t a perfect science, but they do start to help us isolate that lameness to a particular region. Your vet is looking to see if the lameness worsens after a particular manipulation. The reason the test would make the lameness worse is because it stresses the joints and the associated soft tissue structures. If there’s some type of injury or other issue present in that location, that extra stress or tweaking is going to be more uncomfortable when the horse first trots off.

[12:52]

When we do these manipulations, we’re putting tension or compression on the soft tissue or the joint surfaces, increasing pressure inside the joint, constricting blood flow when holding in a tight flexed position, and stretching the nerves a little bit. All of these things are meant to put stress on that region of the limb and make the lameness temporarily more apparent so that we can see it.

[13:30]

After flexions, your vet may want to perform what’s called diagnostic anesthesia to further isolate or confirm the region to which that lameness localizes. You probably know these better as nerve blocks. Your vet will inject a small amount of a numbing agent — usually carbocaine — around the nerves in the leg, or potentially directly into a joint. Just like when you go to the dentist and they numb you up, it’s the same concept — this will temporarily numb the structures innervated by those nerves.

[14:21]

When performing nerve blocks, your vet will start from the bottom of the limb and work their way up. Everything below that point of numbing will become numb, so starting at the bottom allows isolation of regions individually as you move upward. This helps isolate more accurately. There are many different blocks that can be performed — whether perineural (nerve blocks) or into a joint itself. Usually, your vet will only do three, maybe four max, in one day. For more complicated cases, a lameness workup might stretch over two days, or the vet may come back to continue. If the horse at any point “blocks out” — meaning it trots sound after being blocked — then the source of the lameness is isolated to the region that block targeted.

[15:32]

Last on our list for lameness workup is diagnostic imaging. Once you’ve isolated the lameness to a particular region, using X-rays or ultrasound will help your vet reach — or at least hopefully reach — a definitive diagnosis as to what’s causing the lameness. This will help guide your treatment plan and prognosis, which is especially important for performance horses. In some tricky or complex cases, advanced imaging like CT, MRI, or a bone scan may be needed — something your vet will discuss with you if all other steps aren’t yielding a diagnosis.

[16:29]

Now we’re on to the final leg of our lameness workup: resolution. There are many causes of lameness in horses, and the treatment plan will depend entirely on the underlying cause. For mild to moderate lameness, possible causes include hoof abscess, laminitis, navicular syndrome or pain, osteoarthritis (from any joint or in the neck), or soft tissue injuries like a bowed tendon or injury to the suspensory ligament, superficial digital flexor tendon, or deep digital flexor tendon, and even muscle strain.

[17:31]

For more severe lameness — non-weight-bearing cases — possible causes still include hoof abscess and laminitis, but also more serious conditions like cellulitis (a dermal skin infection, which horses are prone to if they get a nick or wound on a leg), synovial infection (a bacterial infection in a synovial structure such as a joint, tendon sheath, or bursa, often from a penetrating wound), and, of course, fractures. These examples aren’t set in stone — some horses will surprise you and be more or less lame than expected once a diagnosis is made — but they’re general guidelines.

[18:45]

Depending on the cause, the treatment plan might include some combination of: rest, cold therapy or cold hosing, compression bandaging, systemic anti-inflammatories, joint injections, antibiotics, other indicated medications, therapeutic shoeing, complementary modalities like shockwave or laser therapy, and even surgery, depending on the case.

[19:25]

All right, you guys, that wraps up the totality of lameness exams in horses. There are a lot of steps, and these appointments can take a while, but hopefully you’ll feel more prepared for when you need to call your vet for a lameness workup. Here are references for today, and I really appreciate you taking the time to listen. Don’t forget to like and subscribe to our channel, explore the other videos we have, and check back regularly — we have new stuff coming out all the time. Also, check out the additional links I’ve provided in the description below — there are supplemental materials on lameness exams in general, as well as more in-depth discussion on flexions and diagnostic anesthesia if you’re curious. Be sure to check back soon for another video. Thanks so much — bye!