image Visual Assessment of Lameness: Limitations and Pitfalls

Acceptance & Resistance of Lameness Measurement – Seasoned Lameness Experts Sound Off

By Nancy S. Loving, DVM

Wellness exams and lameness evaluations often pose challenges for equine practitioners to pin down the root of a horse’s problem. Get it right and the client is forever indebted and is quick to voice confidence in your skills. Get it wrong, and they may abandon your practice and look elsewhere for veterinary expertise.

Yet, in today’s diagnostic armamentarium, there is a powerful tool that has the potential to increase not just client confidence in your expertise but also your own confidence in developing a diagnosis. Inertial sensor systems provide an objective analysis of a horse’s gait. Despite access to this helpful tool, there may be pushback amongst horse owners and veterinary colleagues about its use. We thought it could be helpful to investigate the degree of resistance, how equine practitioners deal with reluctance (or not) to accept this technology, and how they find it benefits their practices.

Daily Use and the Learning Curve

Mark Baus, DVM of Grand Prix Equine in Connecticut focuses most of his practice on hunter/jumpers while performing solely lameness work. He uses the Equinosis Q on every single lameness exam, which means it’s in use constantly, and has for over 10,000 lameness trials through his career. He notes that it improves his work, and he stresses that he never pursues diagnostic blocks or prepurchase exams without using it.

Baus comments that he doesn’t make a big issue to his clients for using it. While he is taking the horse’s history, his assistant puts the system on the horse so seamlessly that clients don’t even notice, especially since it is very unobtrusive. He always discusses with the client what he sees subjectively before he reviews and discusses the findings from the Q.

Roland Thaler, VMD, DACVSMR of Metamora Equine PC practices in Metamora, Michigan and is enthusiastic about use of the Q. He says the device is exceptionally useful especially since many times the problem is in more than one limb and/or is multifactorial with a combination effect of limb asymmetries. It helps differentiate lameness into components to validate (or not) what he “sees.” Like Baus, as Thaler collects history from a client, he places the sensors on the horses. He feels the Q keeps him “honest” by providing objective information with accountability. He feels it saves time and improves his productivity, so he also won’t practice without it.

Some practitioners own the Equinosis Q and only bring it out for difficult cases. Thaler points out that a practitioner may not know they are dealing with a difficult case until they are well into the lameness exam and proceeding with diagnostic joint or nerve blocks. With that in mind, he advises to start the exam with the sensors in place to gather baseline information.

Scott Hay, DVM, a racetrack practitioner with Teigland Franklin & Brokken in Fort Lauderdale, Florida doesn’t try to talk a client into using it. He just puts the sensors on the horse without conversation. Clients’ acceptance level is good, he notes, especially once they see the information generated from the Q report.

Steve Adair, DVM, DACVS, DACVSMR has been using the Q for 10-12 years since its inception. His practice at the University of Tennessee College of Veterinary Medicine focuses not just on clinical patients but also monitoring rehabilitation progress. He sees 15-20 lameness cases a week with over 36 years of equine practice experience. Most cases he sees are referrals from other practitioners. He finds the Q is especially good for multiple limb lameness in conjunction with using his clinical judgment as to which limb asymmetry is the most significant. “It is simply another tool in one’s medicine bag,” says Adair. He not only has had no pushback from clients, but he says they accept and welcome its use in lameness cases. He uses it on most everything except for cases that are so lame that they cannot trot.

Hays’ comment about pushback is particularly interesting: “I find that the biggest pushback is from myself, or similarly from other practitioners’ reluctance to change their ways after decades in practice. People get set in their ways.” This applies to procedural changes that possibly take more time to implement, and he also notes that the daily pace in his racetrack practice is somewhat frantic with many things going on at one time and the need to multitask. It is sometimes necessary to adjust the daily schedule to take more time for a single case. “As creatures of habit, it is sometimes challenging to alter one’s comfort zone,” he muses. “This is true not just for veterinarians but also for trainers and horse owners.”

From a slightly different approach, Adair observes, “I get the most pushback from the lameness itself because most of our workups at the University are complex lameness events that take 2-4 hours to pursue with exam and diagnostics. This is especially true for hindlimb lameness and/or cases needing diagnostic blocks. The biggest complaint I hear is from clients about the duration of the full exam, which is not directly to do with the use of inertial sensors.”

Skill Refinement and Improved Work Productivity

Thaler advises that use of the Q can help to refine skills. He says, “The truth is the truth when achieved objectively.” Lameness is a complex issue with gait asymmetry often involving multiple components and with compensatory issues. While a horse owner may not always recognize multiple component contributions to a horse’s lameness, they do recognize that their horse is not performing well or up to expectations. Time, money and emotion are essential resources at risk, he says, with money seldom being the decider for an owner to proceed; usually it is the client’s time or emotion that decides. “The inertial sensor device helps reduce emotions and allows more productive discernment of the problem,” remarks Thaler.

“For a treating veterinarian, the Q is emotionally stabilizing as it validates the degree and location of an issue and obviates that gnaw of concern that you are missing something during the exam,” says Thaler. “The best part is the gratification that comes through productive time expenditure and helping to minimize time wastage while working.” Thaler advises that the Q holds a practitioner’s feet to the fire even if the “answer” is different from expectation. He points out that the human mind often sees what it wants to see, and this isn’t always correct, especially if performing a complex lameness workup late on Friday afternoon or Saturday when work fatigue sets in, and the vet is anxious to call it a day.

Baus says it is not unusual for him to disagree with the sensors, especially with hindleg lameness. Not only are there possible compensatory gait asymmetries, but he also notes that in many cases, horses experience lameness in more than one leg. “Lameness in one leg often affects another leg, as for example, a LF limb lameness may bring out other aspects of asymmetry in the RH, and conversely, a hind limb lameness will create the appearance of lameness in the front limb on the same side.” Baus also points out that if a horse appears lame on the outside of the circle, especially with a late push-off lameness, then the horse may be lame on the other front leg instead. The Q helps to define such confusing parameters.

The Q is able to pick up on subtle lameness issues that may not be detectable with the naked eye. Baus remarks, “The Q helps sort through subtle and/or compensatory issues.” He advises that the threshold for lameness in a front limb is about 8-1/2 mm, but lameness is only visible to his eye when it is 12-13 mm or more.

While there is a learning curve to use the Q, Hay says it is worth the undertaking. He observes that a common question asked is “Why do I need a computer to tell me what I already know?” Hay explains the advantages of the Q: a) it has increased sensitivity for picking up asymmetry, especially for subtle and/or multiple limb lameness; b) it increases the objectivity of working up a case; and c) it significantly helps to evaluate the response to diagnostic blocks. All these features help increase a practitioner’s level of confidence.

Adair mentions a common misconception of skeptical colleagues is the perception that it adds time to the exam. “Those not used to incorporate it into lameness exams feel it takes time.” In contrast, he believes it saves time because one doesn’t need to pursue a lot of lunging or flexion testing because the Q is able to identify quickly which limb or limbs are asymmetric. For his students, he still pursues lunging and flexion testing for their learning experience. Adair remarks that some practitioners aren’t comfortable using technology and prefer to use their subjective eyes on the horse. However, he emphasizes that the Q does not substitute for a practitioner’s clinical judgment of an exam.

Use for Further Diagnostics, Treatment Response, or Prepurchase Exams

The Q not only helps measure the degree of lameness, but it also creates a baseline for evaluating diagnostic blocks or response to treatment. The increase in confidence observed by Hay helps verify what a practitioner thinks he or she sees and directs one to pursue joint or nerve blocks in a specific area. The Q helps verify changes from blocks, especially for lameness that is a subtle Grade 1 out of 5.

Thaler stresses that the inertial sensor information enables him to continue anesthetic blocks in an effective, progressive, and productive manner with information coming immediately without the need to repeatedly re-evaluate partial improvements during the diagnostic blocking process. 

The trial reports help assess progression of a lameness, either getting better or not, advises Baus. He also uses the Q prior to joint injections, particularly when dealing with cases he’s seeing for the first time to help corroborate a correct approach. Following a joint injection, he can do a reevaluation to check efficacy and to establish changes from baseline.

Another benefit Baus has found, especially when looking at a front leg impact lameness, is that if the red line (Vector Sum of minimum and maximum head position) approaches the “equator,” i.e. where it is difficult to differentiate between right and left forelimb lameness and the horse has been  blocked up to suspensory ligament without improvement, then he looks to a neck problem – the gait asymmetry or “lameness” may result from compensation in movement due to spinal pain. “Currently, it seems that necks are commonly diagnosed and treated, maybe more than necessary, yet the Q substantiates following that line of diagnosis,” says Baus. Thaler concurs, “The Q helps isolate distal limb issues so focus can be placed on the axial spine (neck/back/sacrum) when appropriate.”

Thaler feels that objective documentation may provide legal protection especially for prepurchase exams because it removes subjective assessment while documenting the gait at the time of the exam. It also provides a baseline for comparison at later assessments. For prepurchase exams, he says it mitigates personality conflicts, especially between seller and buyer regarding the presence of gait asymmetries.

In contrast, Adair doesn’t use the Q for prepurchase exams since it measures asymmetry, not pain. He notes that it is sometimes difficult to tell if an asymmetry is due to a mechanical, pain, or neurologic problem or from a rider-elicited issue. He has concerns that if the Q picks up a mild asymmetry, then the buyer and owner may have increased concerns about a potentially subclinical gait abnormality that may have little significance for a horse being able to perform its job.

Another excellent application of the Q inertial sensor system noted by Baus is for wellness workups and prior to a competitive season to help devise a plan for owners and trainers to implement for pleasure and performance equestrian pursuits.

Thaler also uses the Q to provide a metric for rehabilitation to help develop a structural program. A horse’s performance can be monitored through repeated measurements to enable proactive protocols to be implemented.

Similarly, another of Adair’s primary objectives is to use the Q as a therapeutic monitoring device to compare results of intervention. He calls it a great “memory tool,” which is especially useful for weekly evaluations following an initial baseline report. The reports indicate whether the physical and therapeutic regimens are helping or if it is necessary to back off on the work intensity through the rehabilitation process.

Using the Q Reports as a Communications Tool

Adair emphasizes that clients love the graphic representation from the report generated by the Q software. This is especially helpful because with COVID-19, clients aren’t allowed into the vet school building to witness the lameness proceedings so he can bring out the report on the tablet and demonstrate to the client the results of the exam and diagnostic blocks.

As for the students, Adair notes that they don’t see the Q report until after they make a subjective assessment. The same process is used for diagnostic blocks. “It is great that this technology can give students first hand feedback right then and there,” he says.

“The Q report has a ton of information that is easy for clients to understand,” says Baus. The system can store the report into folders on the machine and then Baus puts it into a Dropbox to send to the client. He also feels that having a prepurchase exam report on file can provide protection for veterinarians. He doesn’t use euphemisms like “stiff” or “short” in his discussions with clients. A horse is lame or not lame, and while some sell a perfectly sound horse for perfectly good reasons, for prepurchase exams, it helps to sort through gait abnormalities that could impact a horse’s work.

Pushback from Clients, Trainers, and Veterinary Colleagues

Thaler says he gets zero pushback from clients, and in fact, horse owners in the barn get interested by the sensors and are curious how it works. The occasional pushback comes from sellers when he uses it for prepurchase exams.

The only pushback Baus has experienced is from a couple of trainers when he used the device before he was familiar with the system and he was not able to explain the discrepancies. This caused a loss of confidence by the trainers and they carry that concern forward into the present, even years later. He says that trainers, in general, are often shaken when the “human element” is perceived to be removed in the evaluation of lameness cases.

Some veterinary colleagues are resistant to using it, possibly because of concerns regarding its cost, and also an impression that it takes time to use. Thaler comments that there may also be reticence to use it because of a feeling of inferiority for having to lean on a device to help with decisions. Some colleagues have also remarked that “this is a cheater’s way to identify lameness.” Thaler notes that colleagues often think they don’t need to use inertial sensors and are way overconfident in their own abilities – this is especially true of young veterinarians.

In spite of time constraint concerns by practitioners, Hay feels the increased sensitivity of the technology is particularly helpful to racehorse injuries. However, rather than trainers being amenable to using it for comparisons of a number of works to a baseline evaluation, they seem to prefer to just see how a horse goes rather than “looking for something.” Some trainers may not be clear how to interpret the information, but it is helpful to use a technology that is sensitive to picking up subtle gait changes. Part of his job is to help educate racehorse trainers in the value gained from use of the Q. Hays says that the Q is more objective and can answer a lot of questions. One example he cites is cannon bone bruising, which is difficult to diagnose without advanced diagnostic imaging, yet the Q can pick up gait asymmetry related to this kind of problem and help point in the direction for appropriate diagnostics. Another help is with a multiple — quadrilateral or bilateral – limb lameness.

Cautionary Notes

The clinicians note some cautions when using inertial sensors as the standard of care.

While the Q produces repeatable results, Thaler advises “not to let it think for you.” It is best used to validate observations. He recommends paying attention to the horse and its history and also to watch how an owner handles the horse on lunge and trot-out as that could confound the results – for example, if the horse is jumping around, doesn’t keep a consistent trot, or throws its head. Thaler comments, “Some horses don’t move consistently enough for the Q to be effective. In some cases, it’s necessary to put a rider up to add that dynamic to evaluation of the symmetry of gait. In some cases, asymmetry only shows up under saddle.” He finds it useful to do flexions with a rider mounted.

While Equinosis inertial sensors are water resistant, they are not waterproof. They cannot be submerged in an underwater treadmill or if the pastern sensor stands in a deep puddle.

It is important to keep the equipment charged, and this can be challenging when considering all other veterinary practice equipment that has a similar need.

While it has a substantial price, Thaler feels that the increased productivity of his practice adds value to appointment times and is especially important for comparisons of a horse to itself over time.  But there is also the philosophical conundrum – not everyone wants to integrate and interface with technology in their practice.

In a perfect world, Thaler says you’d have perfectly even terrain for lameness evaluations but in his Michigan practice, this is rarely the case – he seldom has a hard or firm surface on which to work a horse. In many cases, the horses work in arena conditions with somewhat soft footing. Still, he feels the Q produces great information.

“The Q provides the best efficacy when used consistently so a practitioner develops an understanding of the nuances of the report,” says Adair. As some examples of things to remember in its use: a) an ipsilateral fore and hind limb lameness generally indicate that the primary lameness is in the rear limb; b) it is important to remember to have the horse trot at least 25 strides; and c) following a flexion test, the horse should trot at least 10 strides.

“One issue with the system,” remarks Baus, “is that each trial has a standard deviation that defines the validity of the report. At the bottom of the report it states mild versus moderate versus strong evidence. [Editor’s note: This is a qualitative interpretation of the statistical significance of the trial given the standard deviation of the data.]  There then needs to be an explanation or substantiation to make it a good legal document. If there is a question on results, it is best to redo the trial.” [Editor’s note:  One trial represents a 95% confidence interval. Two successive trials with similar results increase the confidence to 99%.]

Fee Strategies for Lameness Measurement Services

To his clients, Baus describes the Q as a “measurement tool” that uses sensors to help measure lameness and location. The invoice states: “lameness detection with inertial sensors.” This is bundled all in one as a lameness exam, so clients don’t have any pushback with fees charged for this. He claims it generates enough revenue to pay for itself each year.

Thaler also does not charge a separate fee or line item for using the Q for gait evaluation. Then, there is no opportunity for clients to push back on its use based on cost.

On the University of Tennessee invoices, Q is built in as part of a lameness exam. There are three tiers of lameness exam based on the amount of time spent and the diagnostics pursued. The Q is used in most every case.

Take Home Message

For practitioners who see lameness conundrums on a regular basis, these four equine practitioners are highly enthusiastic about incorporating the Q routinely into lameness and soundness exams.

While there is a learning curve and a price tag to invest in the equipment, they all concur that is well worth it, as it improves not only productivity in a practice but also helps to more accurately pinpoint the areas of concern.

This is beneficial to the horse and the owner/trainer, as well as being gratifying to the practitioner to be able to resolve a horse’s issues of pain or discomfort. They all remark that clients greatly welcome the use of this technology for tracking down a horse’s soundness issue.

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