Page 213 - Equine Clinical Medicine, Surgery and Reproduction, 2nd Edition

188 CHAPTER 1

VetBooks.ir 1.359 horses that improve on intra-articular analgesia of
the TC joint should be thoroughly investigated in
order to identify the core pathology. If less invasive
imaging does not reveal the cause of lameness, such
cases are good candidates for arthroscopic explora-
tion. Some clinically significant OCD lesions will
respond to conservative treatment such as rest,
systemic NSAIDs and intra-articular medications
including sodium hyaluronate and corticosteroids.
Those cases that do not respond, or where there
are large lesions or increased lameness, are candi-
dates for arthroscopic examination of the joint and
surgical removal of loose fragments and damaged
cartilage.

Prognosis
The prognosis varies with the aetiology of the con-
dition, but in OCD is determined by the size and
position of the lesions, whether they are bilateral,
the use of the animal and whether secondary OA
Fig. 1.359 Dorsoplantar radiograph of a yearling occurs. The prognosis is guarded for conservative
crossbred horse that presented with moderate treatment of all clinically significant lesions. With
tarsocrural joint distension and mild lameness. The surgical treatment the prognosis is good for distal
lameness was localised to the joint by intra-articular intermediate ridge and malleolar lesions but guarded
analgesia and this radiograph reveals a medial malleolar for trochlear ridge lesions.
OCD lesion just visible as a small defect and separate
osseous fragment on the articular margin of the FRACTURES AND LUXATIONS
malleolus (arrow). (Photo courtesy Graham Munroe)
Definition/overview
lesions of the periarticular soft tissues, including Fractures of the hock include the medial and
the collateral ligaments, but a thorough examina- lateral malleolus of the distal tibia (Fig. 1.360), the
tion requires experience and a good knowledge of talus (Figs. 1.361, 1.362) and its trochlear ridges
the local anatomy. In the absence of radiological (Fig. 1.363), the calcaneus (Fig. 1.364), the cuboidal
or ultrasonographic abnormalities, more advanced tarsal bones (Fig. 1.365), osteochondral fractures of
imaging modalities (e.g. scintigraphy, CT and MRI) the talus and incomplete or, less commonly, com-
or arthroscopic examination may reveal a cause. plete articular fractures of the dorsoproximolateral
aspect of the third metatarsal bone. Luxation or
Management subluxation may occur at the level of the TC, PIT
No treatment is required if an inciting cause is not (Figs. 1.366, 1.367) or tarsometatarsal (Fig. 1.368)
identified and the horse is sound. Treatment may joints, with or without a concurrent fracture of the
be attempted if the owner finds the condition cos- hock. Luxation of the DIT (centrodistal) has not
metically disturbing. Drainage of synovial fluid via been reported.
arthrocentesis, intra-articular medication with cor-
ticosteroids and/or hyaluronan, pressure bandaging Aetiology/pathophysiology
of the hock and restricted exercise may prove suc- The hock is heavily invested by dense soft-tissue
cessful. However, in many cases the effect of such structures that cover the bones and provide good
treatment on joint distension is short-lived. Lame support. Fractures and luxations of the hock are