Page 1207 - Adams and Stashak's Lameness in Horses, 7th Edition

Miscellaneous Musculoskeletal Conditions 1173

unwanted variables. A percentage of horses will not dis­ acquired prior to administering any sedation. Ancillary
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play lameness until they are ridden. This may bring sub­ testing procedures must be interpreted relative to the
VetBooks.ir visible. The horse can also be put under more strenuous animal being examined.
tle lameness to the surface that may not otherwise be
physical exam findings and relevant to the history of the
There are no required standards for imaging in the
demands giving the examiner the opportunity to perform
a post‐exercise physical examination. PPE. The recommendations for imaging are based on a
A particularly difficult and oftentimes uncomfortable number of factors including the signalment of the horse,
situation is recognizing and confidently documenting past and present performance, previous medical history,
the presence of subtle neurologic deficits. During the intended purpose for the horse, results of the initial PPE,
static exam, evaluating for such signs as symmetric or communication with the prospective buyer, and budget­
asymmetric muscle atrophy, abnormal posture, or ary constraints.
abnormal hoof wall wear can give clues to possible cen­ Radiography is the most utilized imaging modality in
tral, peripheral nerve, or muscle disease. In the standing the PPE. It is common for a prospective buyer to come
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horse, the veterinarian can evaluate the cervicofacial/ to the exam with a list of requests for imaging, regard­
auricular and cutaneous trunci reflexes as well as tail less of the exam findings. If left up to the recommenda­
tone, perineal, and anal tone reflexes. The veterinarian tions of the veterinarian, the question of if or what to
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should closely observe the horse during the dynamic radiograph is generally based on the same above crite­
exam for subtleties that might indicate proprioceptive ria. If the initial examination fails to identify any abnor­
deficits. Evaluation of stops and starts from the walk, malities, radiographic evaluation is used to scan for
transitions from the walk to trot and trot to the preexisting or potential future issues. The most thor­
walk, tight turns, and backing the horse can help detect ough evaluation would include complete studies of the
subtle neurologic deficits. The goal is to determine if the front feet, bilateral carpi, tarsi, and stifles, all four fet­
horse travels symmetrically, smoothly, and with appro­ locks, and cervical and thoracolumbar spine. This num­
priate stride length and foot flight, if the horse appears ber of imaging studies would add considerable expense
strong and consistently places the feet appropriately, to the exam, and the veterinarian must keep in the mind
and if the horse moves in a balanced and coordinated radiation safety issues.
fashion. It can be difficult to differentiate whether A few examples of radiographic studies that might be
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asymmetry and weakness are due to musculoskeletal recommended by a veterinarian assuming relatively nor­
pain and weakness or neurologic deficits. Horses with mal physical examination and dynamic examination are
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musculoskeletal pain tend to be consistently irregular, given below:
whereas horses displaying neurologic gait deficits tend
to be much less consistent and make variable mistakes • 14‐year‐old Quarter horse gelding: Bilateral front feet
navicular series, bilateral tarsi, and bilateral stifles
when positioning their limbs. 18
Step Five: Diagnostic Testing • 4‐year‐old Warmblood mare: All four fetlocks, bilat­
eral tarsi, and bilateral stifles
There are a number of factors to be considered when
requesting or recommending additional diagnostic • Young off‐the‐track Thoroughbred: Bilateral carpi, all
four fetlocks
testing. Knowledgeable buyers often come to the PPE
requesting specific ancillary testing regardless of the Recommendations for cervical spine and thoracolum­
examination findings. Less knowledgeable buyers may bar radiographs should be discussed with the buyer if
be advised by their primary veterinarian, trainer, or evidence of back pain and reduced range of motion in
friends as to what type of ancillary testing to request. the neck are discovered during the examination particu­
The examining veterinarian will usually discuss with the larly in jumpers and dressage horses. 14,15 Shoes should
prospective buyer ancillary testing that he/she recom­ be removed if radiographs of the feet are to be taken
mends based on the findings of the basic examination. preferably by someone that is skilled in properly remov­
Their recommendations are often based on a number of ing horseshoes or by a farrier. Regardless of who removes
factors, such as age, breed, intended purpose of the the shoes obtaining the owner’s signed consent is neces­
horse, and abnormalities that were identified during the sary, and if consent to remove the shoes is refused, a
PPE. The decision to perform the recommended testing refusal statement should be signed and included in the
is up to the prospective buyer. If the prospective buyer report. 25
refuses additional testing, the conversation, decision, All radiographs should be of high quality, well posi­
and reason for the refusal should be documented in the tioned, and labeled correctly. Including poor‐quality
final report. radiographs in a PPE is inappropriate and a potential
Following completion of the basic PPE, any addi­ source of litigation. If the radiographic studies are per­
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tional testing that was recommended or requested in formed by technical personnel, the veterinarian should
Step 1 or 2 can be performed. Depending on the veteri­ approve each image before including them and signing
narian’s capabilities and facilities, additional testing that off on the final PPE report.
is commonly performed may include upper airway Abnormalities are commonly identified on PPE radio­
endoscopy, musculoskeletal ultrasound, and echocardi­ graphs that do not correlate strongly with potential lame­
ogram. Advanced imaging can be considered if a specific ness. This can make interpretation and reporting difficult
finding is to be investigated further. In the future nuclear in the final report. In this instance, if the veterinarian is not
scintigraphy and magnetic resonance imaging (MRI) comfortable interpreting the findings as it relates to con­
may become common practice in PPEs. 10,14,15 Obtaining tinued soundness or potential unsoundness, seeking a sec­
blood for the purpose of drug screening should also be ond opinion is advised. The relative importance of any
addressed with the prospective buyer and the blood radiographic finding that is considered abnormal, or not