Page 1009 - Adams and Stashak's Lameness in Horses, 7th Edition

Occupational‐Related Lameness Conditions 975

in the racing Quarter horse. This includes flexing the Intra‐articular anesthesia may be used to localize the
carpus with the leg in a raised position so that the radius lameness. Radiographs are frequently normal but may
VetBooks.ir response of the neck and shoulder muscles as a response syndrome changes. Problems associated with post‐rac­
show some degree of pedal osteitis, and rarely, navicular
is horizontal and looking for an immediate withdrawal
ing arthrosis usually occur 1–2 days after racing, when
to pain. Directly palpating the carpal joints by placing
the thumbs along the individual dorsal borders of the lameness is quite severe. Anti‐inflammatories, ice, and
carpal bones while the fingers apply pressure behind the systemic corticosteroids tend to correct the lameness
joint can further localize the lameness. The coffin joint is within 12–24 hours.
palpated for heat and excessive joint effusion, and the Anti‐inflammatory medications and corrective shoe­
digital pulse should always be checked because it is fre­ ing are often used to treat the condition. The shoeing is
quently elevated in horses with acute foot problems. A in accordance with individual needs, most commonly
positive Churchill test may indicate hock soreness and is backing up the shoe as much as possible and protecting
quickly performed while palpating the distal limb. The the sole. A wide variety of pads are employed with vari­
medial femorotibial joint is the most common area of ous sole packings. Wedge pads or shoes may be used to
soreness in the stifle and may or may not have effusion. correct the low‐heel conformation, but care must be
The history of a poor performance (especially leaving taken as often the heel pain is exacerbated. Some horses
the gate) usually initiates a more complete examination are trained in bar shoes until they are ready to race.
of the hindlimb. Diagnostic blocks are used when neces­ NSAIDs (phenylbutazone in particular) are useful, and
sary to localize the lameness. See Chapter 2 for more the feet are iced twice daily during the acute stage.
details. Intra‐articular corticosteroids are effective in relieving
the lameness. Betamethasone esters (Betavet ) or triamci­
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nolone acetonide (Vetalog ) and isoflupredone acetate
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SPECIFIC LAMENESS CONDITIONS (Predef ) with or without HA are commonly used, espe­
cially if frequent joint injection is necessary. Frequent use
The lameness conditions discussed below are the of methylprednisolone acetate (Depo‐Medrol ) in the
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most relevant for the Quarter horse racing breed. Most coffin joint can produce severe cases of OA over time.
of the topics are covered extensively in other chapters; Medial heel bruising is very common. Treatment by
therefore, this section is meant as a review of Quarter quartering shoes short term can become a major source
horse injuries and how they differentiate from of lameness in the long‐term due to the time required to
Thoroughbreds. grow out heels and correct shoeing imbalance. Other
differential diagnoses of the foot include bruises,
Arthrosis of the Distal Interphalangeal (DIP) Joint abscesses, grabbed quarters, quarter cracks, and lamini­
and Problems Associated with the Foot tis. See Chapters 4 and 11 for further details on lame­
ness conditions of the foot.
Coffin joint synovitis is a significant cause of lame­
ness in the Quarter horse. The breed is well known The Metacarpophalangeal (MCP) Joint
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for having undersized feet in relation to the body size,
which, coupled with the tendency for racehorses to The MCP joint is another frequent site of lameness in
develop long toes and excessively sloping heels, prob­ Quarter horses. The most common conditions are syn­
ably leads to greater stresses to the foot than in other ovitis/capsulitis, osteochondral chip fractures, osteo­
breeds. They also tend to have short upright pasterns, chondritis dissecans (OCD), OA, and fractures of the
and they race at high speeds on firm track surfaces. proximal sesamoid bones.
Bilateral forelimb lameness is seen, and it can be Heat and synovial effusion are the first signs of syno­
accentuated by jogging on a hard surface. The stride vitis, along with a varying degree of lameness. The con­
is shortened with a transfer of weight to the hindlimbs. dition is often bilateral and radiographic examination is
Horses typically respond to hoof testers over the cen­ negative. Capsulitis does not occur as frequently as in
tral third of the frog (as in navicular syndrome). An the Thoroughbred because Quarter horses in training
increased digital pulse is usually evident, and DIP gallop less than Thoroughbreds do; therefore, much less
joint effusion may be palpated above the coronet in stress is placed on the soft tissue structures of the fetlock
many cases. Younger horses (2‐ and 3‐year‐olds) with joint. Symptomatic treatment includes the use of ice, leg
synovitis show a greater degree of localizing inflam­ sweats or poultice, and NSAIDS. Intravenous HA
matory signs than older horses with chronic osteoar­ (Legend ) or IM PSGAG (Adequan ) are often used as
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thritis (OA). 12 systemic treatments. Intra‐articular therapy is very effec­
OA of the DIP joint is occasionally evidenced by the tive in these cases, with a good response from corticos­
presence of osteophytes involving the distal aspect of the teroids with or without HA. If the condition does not
middle phalanx or the extensor process of the distal resolve with intra‐articular therapy or if it recurs after a
phalanx. Generalized suspensory soreness as well as brief period of time, the training program should be
soreness in the area of the bicipital bursa is often pal­ altered or the risk of further joint damage is likely, with
pated secondary to inflammation of the DIP joint. Back OA as the end result.
pain may also be associated with the presence of sore Many 2‐year‐olds are entered in multiple futurities,
feet and can be detrimental to racing performance due so training revolves around these races. Trainers try to
to the horse’s reluctance to break sharply and extend its keep horses on schedule for their race dates without sus­
stride. These secondary clinical signs usually disappear taining injuries that jeopardize their careers or require
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after resolution of the foot soreness. extended lay‐up periods.