Page 202 - Equine Clinical Medicine, Surgery and Reproduction, 2nd Edition

Musculoskeletal system: 1.4 The forelimb 177

VetBooks.ir Clinical presentation 1.339
Affected horses show moderate-severe forelimb
lameness localised to the shoulder region.

Differential diagnosis
Shoulder OA; luxation.

Diagnosis
Diagnosis is suspected based on clinical signs and
signalment. Radiographic findings of a shallow gle-
noid cavity on mediolateral radiographs and mea-
surement of the curvature of the glenoid cavity can
be performed to confirm the diagnosis (Fig. 1.339).
Affected cases commonly have radiographic evi-
dence of OA and occasionally signs of subluxation.

Management
Cases can be managed palliatively or through Fig. 1.339 Mediolateral radiograph of the shoulder
arthrodesis of the scapulohumeral joint. Severe cases region showing abnormal contour of the scapulohumeral
may require euthanasia. articulation consistent with dysplasia. In addition, there
is new bone formation at the caudal aspect of the scapula
Prognosis suggestive of secondary joint disease.
Prognosis is poor due to development of secondary OA.
1.340
SUBLUXATION

Definition/overview
Subluxation of the scapulohumeral joint.

Aetiology/pathophysiology
Subluxation can be due to trauma or associated with
dysplasia of the scapulohumeral joint.

Clinical presentation
Affected horses show an acute and severe lameness,
often non-weight bearing. Longer standing cases
quickly show muscle atrophy. Palpation is resented,
and an abnormal range of movement can be detected
on manipulation. An irregular contour to the shoul-
der region may be observed.

Differential diagnosis
Intra-articular fracture; synovial sepsis.
Fig. 1.340 Mediolateral radiograph of an 8-year-old
Diagnosis miniature horse with a 1-month duration of severe
Diagnosis can be confirmed radiographically right forelimb lameness showing subluxation of the
(Fig. 1.340). Luxation usually occurs cranially scapulohumeral joint.