Page 241 - Equine Clinical Medicine, Surgery and Reproduction, 2nd Edition

216 CHAPTER 1

VetBooks.ir 1.412 1.413

Fig. 1.413 Ultrasonographic image of the
coxofemoral joint of a horse with osteoarthritis.
Fig. 1.412 Ventrodorsal radiograph, taken under The white line to the right is the femoral neck
general anaesthesia, of the coxofemoral joint of and the line to the left is the acetabular rim. The
a horse with osteoarthritis of the joint. Note the hyperechoic white fragmentation centrally is
margin osteophytosis on all aspects of the acetabular osteophytosis at the margin of the femoral head
rim and the femoral head. (Photo courtesy Henk van (right) and acetabular rim (left). (Photo courtesy
der Veen) Henk van der Veen)

risks during recovery from the anaesthesia. If luxa- Diagnostic arthroscopy can be performed, but for
tion is ruled out and in other chronic cases where horses weighing >300 kg, special long instruments
OA has developed, intra-articular analgesia of the are required. Round ligament injury is often only
coxofemoral joint should be performed to localise definitively diagnosed at post-mortem examination.
the joint as the source of pain. This procedure can be
challenging, although easier under ultrasonographic Management/prognosis
guidance, and will usually only improve the lame- Closed reduction of a coxofemoral luxation can be
ness rather than completely abolish it. Ultrasound achieved under general anaesthesia in acute cases
examination of the articular regions of the acetabu- only. In chronic cases the acetabulum fills in with
lum and femoral head is possible and helpful where granulation tissue, preventing relocation of the fem-
X-ray machines of suitable power are not available. oral head back into position. The joint may dislocate
It is particularly useful to identify subluxation or again either during recovery or within a few days.
luxation, femoral neck or head fractures and periar- Various surgical procedures for open reduction can
ticular changes of OA (Fig. 1.413). Nuclear scintig- be attempted, but the prognosis for athletic function
raphy can be performed if a fracture is suspected or is poor. There is no effective treatment for rup-
if the results of the intra- articular block are equivo- ture of the round ligament apart from arthroscopic
cal. Scintigraphic findings, however, have to be cau- debridement and medication of the joint with corti-
tiously interpreted because of possible differences in costeroids, which is also suitable for horses with OA.
muscle mass. Caudal oblique views are often help- The prognosis in these cases is guarded to poor for
ful. Definitive diagnosis of OA, OCD, OCLL and OA and often hopeless for ligament damage. In hip
hip dysplasia requires high-quality radiographs to dysplasia, OCD and OCLL the predisposition to
be obtained, often under sedation in foals or general OA at an early age means the prognosis for athletic
anaesthesia in dorsal recumbency for older animals. function is poor.