Page 1064 - Adams and Stashak's Lameness in Horses, 7th Edition

1030 Chapter 9

(15 mg/kg, PO, every 24 hours, for 14 days). Phenytoin The cause of shivers is unknown, but equine polysaccharide
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has been used to improve the gait abnormality associ­ storage myopathy (PSSM) has been incriminated.
VetBooks.ir musculotendinous junction are best treated with LDE dence of PSSM. Affected horses can be improved with a
A muscle biopsy may be obtained and submitted for evi­
ated with Australian stringhalt.
Horses with traumatic injury to the LDE tendon or
high‐fat, low‐carbohydrate diet. No other treatment for
myotendonectomy. The author prefers to remove the shivers has been shown to be consistently effective, and
LDE tendon along with a 5–6 cm of the distal aspect of most owners learn to live with the disorder.
the LDE muscle belly, thus completely removing the
musculotendinous junction. The inclusion of the muscu­
lotendinous junction seems to lessen the chance for DISEASES OF YOUNG DRAFT HORSES
adhesions between the stump of the resected tendon and
extensor tendon sheath, which may contribute to recur­ Septic Arthritis
rence. The prognosis following surgery is fair to good. Septic arthritis in draft horse foals is not uncommon
and is usually associated with septic omphalophlebitis
Shivers secondary to a patent urachus. The most commonly
affected joints are the hock and stifle, and osteomyelitis
Shivers affects draft horses along with other breeds, is not an uncommon sequelae. The diagnosis and treat­
including Warmbloods. 9,29 It is an unusual problem ment for septic arthritis in draft horse foals is the same
because the horse typically only does it once it begins to as for light breed horses. The prognosis for draft horse
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walk or trot. Affected horses pick up their leg quickly, foals is similar to that for light breed horses, although
toward the abdomen, and tend to shake the limb before the expectations for athletic demand are less.
setting it down. It can be confused with stringhalt and
upward fixation of the patella. Accompanying the flex­
ion of the hindlimb, the tail head may elevate. The Osteochondritis Dissecans (OCD)
abnormal gait can be exacerbated with lack of exercise, OCD in draft horses mimics the condition in light
low ambient temperatures, and increased horse anxiety. breed horses except that the size of the OCD lesion in
The condition can be difficult for the farrier to deal with draft horses is usually larger. The most commonly
because the unexpected flexion of the limb makes limb affected joints are the hock and stifle. Large osteo­
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restraint difficult. The condition can be unilateral or chondral fragmentation of the distal intermediate ridge
bilateral and can be progressive. For some horses, the of the tibia and the lateral trochlear ridge is not uncom­
progressive nature of the condition can make it difficult mon (Figure 9.66). Likewise, for the stifle, large lesions
to stand, especially when the condition is bilateral. involving the lateral trochlear ridge of the femur are not
Clinical signs also can involve the forelimbs. unusual. Standard arthroscopic techniques for the hock

A B

Figure 9.66. Fragmentation or osteochondral defects associated intermediate ridge (arrow) and (B) an extensive subchondral defect
with OCD tend to be very large in draft horses and occur at more involving most of the lateral trochlear ridge (arrows). The horse in (A)
than one location within the joint. (A) A large OCD lesion of the distal also had a large lesion of the lateral trochlear ridge in the same joint.