Page 720 - Adams and Stashak's Lameness in Horses, 7th Edition

686 Chapter 5

of the malleoli are at risk of displacing over time and, primary indications for surgical repair (Figure 5.88).
therefore, may also be ideally managed with lag screw Diagnosis is made by radiographic examination, which
VetBooks.ir jection for complete examination of the calcaneus.
should include a flexed lateral and a flexed skyline pro-
fixation.
Stressed radiographs may help to demonstrate mini-
Fractures of the Calcaneus and Sustentaculum Tali
mally displaced fractures of the calcaneus. Accurate
Calcaneal fractures are almost always the result of determination of the fracture configuration of the calca-
some external traumatic event leading to injury to the neus is necessary to help provide a prognosis and deter-
TC. Kicks that impact a fixed object such as walls, mine if surgical repair is possible.
doors, fences, or machinery can injure the calcaneus and The prominent ST is positioned on the medial aspect
often lead to open fractures. Skin lacerations may result of the tarsus. The tarsal canal is formed by the ST of the
from the fracture fragments penetrating the skin from calcaneus dorsally, the TC laterally, and the flexor reti-
the interior or from the fixed object externally. The clini- naculum plantar and medially. The ST is prone to injury
cal signs reflect the severity of the bony derangement from direct trauma. In the event of a fracture of the ST,
and possible secondary complications. Swelling and involvement of the TS and lateral digital flexor tendon
crepitus can be severe with major fractures. Significant (LDFT) should be evaluated. 30,47,70,123,124 Bone damage
lameness and a lack of Achilles tendon function are the may be confined to the medial edge of the ST and not
affect the TS and LDFT. Larger fractures however can
disrupt the fibrocartilaginous gliding surface and can
lead to damage of the LDFT and are much more serious.
Wounds associated with the traumatic incident may
introduce debris and bacteria into several synovial struc-
tures such as the TS, the TC joint, or possibly the calca-
neal bursa. Any wound in this area should be investigated
for possible synovial involvement as synovial sepsis and
osteomyelitis of the medial border of the ST may occur.
Osteomyelitis, sequestration of fracture fragments, and
chronic drainage are potential complications of frac-
tures in this area (Figure 5.89). Fractures on the medial
surface of the calcaneus and the ST can be difficult to
manage surgically. In cases in which the TS is involved
but not infected, the bony fragments may be removed,
but the trauma incurred often results in a guarded
prognosis.
Tenoscopy allows the exploration of the TS to assess
the presence of tendon injury and to explore the recesses
of the sheath. Some bony lesions might be outside of the
tendon sheath and are best approached by direct cut
Figure 5.87. Oblique radiograph of a horse that had been down and dissection of the fragment. Careful curettage
kicked on the medial aspect of the tarsus. This articular fracture of of the fracture bed and flushing of the tendon sheath with
the medial malleolus was repaired with lag screws. Source: copious amounts of fluids is indicated after fragment
Courtesy of Dr. Gary Baxter. removal. Conservative management is contraindicated,

A B
Figure 5.88. These flexed lateromedial (A) and flexed skyline (B) radiographic views demonstrate a comminuted calcaneal fracture in a
horse that was hit by a car. Both views were helpful in determining the severity of the injury.