Page 683 - Adams and Stashak's Lameness in Horses, 7th Edition

Lameness of the Proximal Limb 649

as may occur from a fall, while a horse is attempting to dorsal recumbency, a hoist can be used to apply traction
jump a fence, or as a result of a horse pulling and twisting and the body weight is sufficient to provide counter-
VetBooks.ir documented SH joint luxation in a septicemic foal with humeral head reduces, after which it should be possible
An audible click may be heard when the
A report
weight.
a flexed limb while the foot is caught.
69,101
23,60,63,101
multiple joint laxity, another cause was a rough recov-
to freely manipulate the joint.
In acute cases, reduc-
50
23,60
ery from general anesthesia, 69,103 and luxation of the SH tion may be accomplished very quickly. In more chronic
joint has occurred following removal of a large supra- cases, gradually increasing traction may be required
glenoid tubercle (SGT) fragment. 12,16 with limb manipulation before reduction is achieved.
63
Arthroscopic examination of the SH joint following
Clinical Signs closed reduction may improve the outcome particularly
if there is evidence of bony debris within the joint on
63
A history of trauma with an acute onset of severe radiography. As such a radiograph should be taken of
lameness is common. 3,12,16,60,101 At presentation, horses the SH joint after the reduction is complete.
typically exhibit a non‐weight‐bearing lameness. An Recovery from anesthesia should be assisted in all
abnormal stance may also be apparent with the elbow cases. Following recovery the horse should have strict
and carpus held semiflexed and the distal limb adducted stall rest for 2 months to allow healing of the joint
or abducted, depending on the direction of the luxation. capsule and surrounding soft tissue structures.
23
The distal limb is adducted when the humerus is luxated Anti‐inflammatories and intra‐articular therapies are
laterally, craniolaterally, or cranially or is slightly indicated. Reoccurrence of the luxation does not appear
abducted if the humerus is luxated medially. A variable to be a problem in the horse. 101
amount of swelling is present in the shoulder region, Repair of a case of chronic subluxation of the SH
depending on the length of time since injury. joint in a minishetty stallion by arthrodesis has been
Muscle atrophy may be most prominent in chronic reported. The chronicity and bony changes acquired
8
cases. One report found prominent muscle atrophy of provided a recommendation for arthrodesis. Arthrodesis
the infraspinatus and supraspinatus muscles 2 weeks of the shoulder can usually be performed in miniature
following luxation of the SH joint. Distortion of the horses with a single broad or narrow LCP (Figure 5.57).
63
normal anatomic landmarks at the shoulder region may
be apparent if swelling is not excessive, which may aid Prognosis
in determining the direction of the luxation. With lateral
or cranial luxation, the greater tubercle and head of the The prognosis for SH joint luxation is considered
humerus may be most prominent, and with medial dis- good for return to soundness following closed reduc-
placement, the lateral lip of the glenoid cavity can be tion and an adequate rest period, in cases in which
palpable. Affected horses generally violently oppose there is not a complicating fracture. In one study, all 6
63
upper limb manipulation. 23,60
Diagnosis
Radiographs should be taken to confirm the diagno-
sis and rule out fracture. Generally an adequate study
can be obtained in the standing horse, and the mediolat-
eral view is thought to be the most informative. The
38
addition of the craniocaudal oblique projection will
allow a better assessment of the direction of the luxa-
tion. Stressed views may assist in diagnosis. Ultrasound
39
examination may also be used to assess the extent of
injury to the soft tissues supporting the SH joint.
Treatment
Ideally, the luxation should be corrected as soon as
possible. General anesthesia is required in most cases,
although there is one report of correction of a SH joint
luxation using sedation in a 5‐day‐old foal with multiple
joint laxity. In foals, pulling the affected limb into
50
extension while an assistant pushes or pulls the humeral
head back into position will generally suffice. The foal
may have to be stabilized with counterpressure applied
the chest or axilla.
In the mature horse, the patient can be placed in lat-
eral or dorsal recumbency. In lateral recumbency the
body can be anchored to a fixed object, and a tension‐
creating device that is attached to the radius or pastern
region to apply traction is used while the operator forces Figure 5.57. Treatment of a chronic shoulder luxation in a
the shoulder back into position. If the horse is placed in miniature horse with an LCP and transarticular screws.