Page 190 - Equine Clinical Medicine, Surgery and Reproduction, 2nd Edition

Musculoskeletal system: 1.4 The forelimb 165

VetBooks.ir 1.308 1.309

Fig. 1.308
Ultrasonography
of the carpal/distal
antebrachium
confirms the physeal
exostosis to be
involving the deep Fig. 1.309 Carpal sheath tenoscopic image of the
digital flexor muscle caudal distal radius showing two enlarged exostoses
belly in the carpal protruding from the caudal bone surface. (Photo
sheath. courtesy Graham Munroe)

RADIAL FRACTURES with or without comminution. Physeal fractures can
occur at the proximal or distal growth plates and can
Definition/overview be Salter–Harris type I (physeal only) or II (physeal
Radial fractures in adult horses include incomplete or and metaphyseal) configurations.
complete spiral, oblique and comminuted diaphyseal
fractures. In younger animals physeal fractures and Clinical presentation
complete diaphyseal fractures (simple, transverse or Affected horses with incomplete radial fractures are
spiral) occur with varying degrees of comminution. usually moderately lame but able to bear weight.
Soft-tissue swelling over the fracture site is usually
Aetiology/pathophysiology evident and if distal enough can be mistaken for a
Most radial fractures are a result of external trauma carpal injury (Fig. 1.310). Horses with complete,
(e.g. kick). The distomedial aspect of the radius is unstable radial fractures are severely lame with
sparsely covered with soft tissues and is a classic place clear instability and crepitus of the radius present.
for a radial fracture following a kick. The caudal A wound may be present, and palpation of bony frag-
aspect of the radius is loaded in compression whereas ments should indicate suspicion of a radial fracture
the cranial and craniolateral aspects are loaded with potential contamination.
in tension, so trauma to the cortical bone leads to
concentration on the caudal cortex through bend- Differential diagnosis
ing forces and potential failure at this point. Overt Carpal fracture; ulna fracture; synovial sepsis; severe
comminution is unusual, but butterfly fragments soft-tissue injury.
can displace, leading to catastrophic failure. Radial
sequestra may also develop after trauma. Foals may Diagnosis
have simple transverse or oblique diaphyseal frac- Physical examination should alert the clinician to
tures due to trauma (e.g. mare standing on the limb) the possibility of a radial fracture. Diagnosis is