Experiences Using a High-Speed Treadmill to Evaluate Lameness

Chapter 98Experiences Using a High-Speed Treadmill to Evaluate Lameness



Benson B. Martin Jr., Sue J. Dyson, Mike W. Ross


The advent of the high-speed treadmill has led to many advances in evaluating equine poor performance in exercise physiology, gait analysis, cardiac disease, and lameness diagnosis.1-5 This chapter describes our experience using a high-speed treadmill for lameness evaluation in the performance horse.


Lameness has been implicated as a cause of poor performance in several studies involving a complete physical examination, lameness examination, and where possible a high-speed treadmill examination.1-3 In one study, 74% of horses were found to have lameness as a component of poor performance.1 In another study, in which horses with no apparent history of lameness were examined because of poor performance, clinically important lameness in 23.9% of horses precluded a high-speed treadmill investigation.2 In a third study, 4.3% of horses sound enough to undergo a high-speed treadmill examination for poor performance were clinically significantly lame after high-speed treadmill exercise.3


In our experience, convincing trainers and owners that lameness is a cause for poor performance can be difficult. Several studies using a shoe model to induce lameness to assess the metabolic cost of pain related to lameness suggested a trend that pain related to lameness may not increase the metabolic cost of exercise, but it does increase the heart rate in response to pain.6-8 However, another study suggested that a metabolic cost of pain and exercise does occur.9 Pain may alter a horse’s ability or willingness to perform up to expectations or previous performance levels.10



Criteria for Case Selection


The most common criterion for a treadmill lameness examination is lameness that occurs at only high speeds or after an extended period of exercise. The treadmill examination is used most commonly in Standardbred (STB) racehorses or endurance horses. However, a treadmill lameness examination can be used in any breed or discipline, although a horse in which lameness is apparent only when the horse is ridden may be unsuitable.


Horses in which a complete lameness investigation, including diagnostic analgesia and appropriate imaging technologies, fails to reveal a diagnosis are potential candidates for treadmill lameness examination. Additional candidates include horses that require considerable work at low, medium, or higher speeds before the lameness becomes apparent, such as endurance horses or STB racehorses. A treadmill lameness examination also may be useful in horses that are fractious or otherwise pay little attention when jogged in hand or ridden. Horses must pay close attention when trotting on a treadmill and therefore have a more even, rhythmical, relaxed gait that is easier to evaluate.



History


Important historical facts need to be ascertained. Some questions are general, and some are use related. Some may need to be repeated in a different order to elicit an accurate answer. Questions may include those listed in Box 98-1.



BOX 98-1 Questions to Ask When Determining History



General Questions



How long has the horse been lame?

When do you notice the lameness?

Does the lameness improve with exercise?

Does the lameness become worse during or after exercise?

Does the horse ever appear to become anxious or frantic?

Does the horse sweat?

Has the horse’s performance level changed?

Has the horse changed how well it performs?

Has the horse changed the style of performance?

Has the horse had any behavioral changes?

Has the horse been treated for lameness?

Has the horse been “tapped”?

Has the horse ever had any joints treated?

Has the horse received any intramuscular treatments?

Has the horse received any other therapy or medication?

How much and for how long?

What has been the response?

Does the horse receive any special supplements (e.g., sodium bicarbonate)?

What type of shoes does the horse wear and why?

Does the horse have any special shoeing or trimming and why?


Use-Specific Questions



Standardbred Racehorses



At what speed is the horse the worst?

At which gait (trot or pace) is the lameness most easily seen?

Is the horse worse on the straight or on turns?

Is the horse worse when turned in the correct direction of the track?

Is the horse worse when jogging?

What is the horse’s normal gait?

Has any change in the horse’s gait occurred, and what is the change?

Is the horse on a line?

Is the horse on a shaft?

Does the horse get into his knees?

Is the horse worse when jogging free legged or in full harness?

Is the horse worse when checked up?

Does the horse use any special gaiting equipment?

Does the horse wear any head poles?

Does the horse wear any other special equipment and why?


Thoroughbred Racehorses



Does the horse bear in or out?

Does the horse break out of the starting gate as well as before?

Does the horse require any special bit or tack and why?

Related posts:

  1. Lameness in Horses: Basic Facts Before Starting
  2. Thermography: Use in Equine Lameness
  3. Counterirritation
  4. Arthroscopic Examination

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Jun 4, 2016 | Posted by in EQUINE MEDICINE | Comments Off on Experiences Using a High-Speed Treadmill to Evaluate Lameness

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