Page 1121 - Adams and Stashak's Lameness in Horses, 7th Edition

Lameness in the Young Horse 1087

may involve bone, cartilage, muscle, tendon and liga­ Physeal Fractures
ment, nerves, and blood vessels. There is no age limita­ Physeal fractures are common due to the relatively
VetBooks.ir days or at any time later; however, most traumatic and weak physeal bone compared with the diaphyseal bone.
tion on pelvic injuries, which may occur as early as a few
Diagnosis of physeal injuries is made on clinical and
septic causes of pelvic lameness occur prior to 4 months
23
of age. Traumatic injuries of the pelvis and coxofemo­ radiographic findings. Clinical signs vary depending on
ral joint may result from rearing, twisting, and falling the degree of instability; they include lameness of vary­
over, with torsional load causing the injury. Tuber coxae ing degrees, pain on palpation, swelling, and occasion­
injuries are typically associated with external trauma ally angular deviation of the limb distal to the fracture.
such as a kick from another horse or striking the area The primary differential for a stable physeal fracture is
during a fall or against a gate post or other fixed object. infectious physitis. Fracture of pressure physes (those
Injuries of the tuber ischii may occur from falling back­ that contribute to longitudinal bone growth) have been
ward or accelerating backward and directly striking or categorized and defined using the Salter‐Harris classifi­
3,6,12
landing on this bony prominence. cation scheme, covered elsewhere in the text.
The gait and degree of lameness depends on the struc­ Surgical repair is necessary in foals with displaced,
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tures involved and their location. Fractures of the pelvis unstable physeal fractures. If adequate reduction and
almost always involve both sides, with one side more stabilization are achieved, the prognosis for future
extensively damaged than the other. Displaced pelvic soundness is good.
fractures are generally non‐weight‐bearing lame during
ambulation on the side with the most damage. When
standing, however, foals generally bear weight on both Long Bone Fractures
limbs and may electively stand on the primary fracture
side. Generally, the tail is set away from the most severely Long bone fractures usually result from external
affected side. If the injury is caudal to the coxofemoral trauma such as a kick or having the limb pinned beneath
joint, the caudal phase of the stride is prolonged and an object while rolling. Rearing and misloading a limb
there is resentment during the cranial phase, whereas the may result in fracture of the tibia, femur, or pelvis. 21,23
opposite is true for injuries of the tuber coxae. Foals Physical evaluation may be diagnostic in foals with
with injuries to the superficial bony prominences such lameness of traumatic origin because unstable fractures
as the tuber coxae, tuber ischii, or greater trochanter of or severe soft tissue injuries cause obvious, immediate
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the femur as well as injury to the coxofemoral joint dis­ clinical signs. If a fracture is suspected, radiographs are
play a pain response on digital palpation. Deeper inju­ necessary to confirm the diagnosis and determine the
ries of the pelvic floor or pubic symphysis may be more severity of the injury. The prognosis for a foal after frac­
difficult to detect on physical palpation. ture depends on the anatomical location of the fracture;
Radiographs are necessary to confirm the presence of the complexity, orientation, and degree of soft tissue
a fracture, and ultrasound may facilitate identification injury around the fracture; and whether the fracture is
of other injured tissue. Nuclear scintigraphy is occasion­ open. 17,21 Secondary problems associated with contralat­
ally used to evaluate pelvic injuries and can effectively eral limb overload from prolonged lameness or from
identify regions of injury, but does not allow identifica­ immobilization often dictate the degree of long‐term
tion of specific fracture types. Injuries of the physes and soundness.
accompanying soft tissue are more effectively identified Although mechanical laminitis is not as common as
by magnetic resonance imaging. in adult horses, it occurs in foals. More common prob­
Treatment for pelvic injury includes stall rest, and the lems include excessive laxity of the metacarpophalan­
duration depends upon the severity of the injury. Once geal or metatarsophalangeal joint, varus deviation, or
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full weight‐bearing returns, controlled exercise in the deformity of the foot, such as underslung or crushed
form of hand walking is beneficial for rehabilitation. heels and overgrowth of the toe. Contracture or exces­
The prognosis for pelvic injury depends upon severity. In sive laxity of the fractured limb associated with disuse
general, the prognosis is favorable, but severe displace­ may prevent future soundness.
ment accompanied by marked soft tissue trauma or sig­
nificant involvement of the coxofemoral joint carries a
poor prognosis. The main differentials for pelvic trauma Developmental Orthopedic Disease
are septic arthritis, osteomyelitis, septic physitis, and
pelvic abscess. Lameness may be associated with DOD in foals. 7,39
Less severe lameness of the hip region is associated In a group of 378 foals evaluated radiographically at
with tearing of the fascia of the lateral aspect of the 6 months of age, 47% were affected by DOD and
biceps femoris or the vastus lateralis muscle. These inju­ 36% by osteochondrosis with some evidence showing
ries produce a transient lameness that manifests as a Warmbloods may be at higher risk. Although osteo­
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shortened gait at a walk. A palpable 3‐ to 5‐cm deficit, chondrosis does not typically manifest until the late
oriented obliquely and parallel to the muscle fibers, is weanling and yearling period, it is occasionally recog­
present, and an associated hematoma may be observed. nized clinically as a cause of lameness in foals less
Treatment is rest and confinement for 1–2 weeks to than 6 months of age. The development of DOD is
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allow any hemorrhage to stop. These tears should not be multifactorial, but there may be some association
drained or opened for fear of sepsis. Rarely, if ever, do with exercise conditions and rapid growth. See ear­
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any long‐term residual effects of these tears manifest, lier sections of this chapter for specific DOD
and future athletic potential should not be affected. conditions.