Page 716 - Adams and Stashak's Lameness in Horses, 7th Edition

682 Chapter 5

of complications of a full‐limb cast application, the limb screws or bone plating. Cast immobilization is usually
can be maintained in a cast for 4–6 weeks if the CLs are combined with surgical management. Open reduction
VetBooks.ir cast is removed, the hindlimb is placed in a heavy cotton mended for tarsal luxations when there are associated
and internal fixation with a plate is usually recom-
intact and 6–8 weeks if the CLs are ruptured. After the
fractures. Surgical arthrodesis of the TMT, DIT, and PIT
bandage with rigid splints for an additional 4–6 weeks
before turnout in a small area is allowed. joints can be achieved by placing a plate on the plantar
Surgical arthrodesis of tarsal luxations can be per- surface of the joint. The plate is placed on the plantaro-
formed to help achieve pasture soundness for breeding lateral aspect of the tarsus and extends from the top of
purposes. 1,105 However, the prognosis is still guarded. the calcaneus to mid‐MTIII.
Surgical techniques described for management of tarsal
luxations in horses include articular cartilage removal
combined with internal fixation using transarticular Slab Fractures of the Small Tarsal Bones
The DT bones are subjected to axial compression,
torsional, and tensile forces during exercise. Their main
function is to absorb concussion and neutralize these
forces. The DT joints resist these forces and are stabi-
lized by a thick layer of ligamentous tissue that sur-
rounds and unites the small tarsal bones. The dorsal
tarsal ligament (DTL) is a major component of these
ligamentous structures. The DTL originates from the
distal tuberosity of the talus on the medial aspect of the
tarsus and spreads out as a sheet over the face of the DT
bones restricting/limiting movement. The dorsal aspect
of the tarsal region also has the extensor bundle com-
prised of the tendons of insertion of cranialis tibialis and
PT and, laterally, the long digital extensor.
Slab fractures of the CT or T3 bones occur most
often in racing disciplines or other high‐speed
events. 101,141 Slab fractures are felt to be exercise‐
induced injuries in racehorses and result from accu-
mulated bone damage on the dorsal aspect of the DT
bones. 141 They occur at similar locations and configu-
rations in the absence of specific trauma (Figure 5.84).
Third tarsal bone slab fractures occur most commonly
in young racehorses with one study reporting the
median age of 2 years. Fractures of the T3 bone are
more common in TB and STB racehorses and are nor-
mally found on the dorsal and dorsolateral aspects of
the bones (dorsomedial to plantarolateral orienta-
Figure 5.83. TC luxation can cause significant soft tissue tion). Tarsal slab fractures do occur in other breeds
injury(s) and secondary fractures that are often so significant and and disciplines but are less likely to be due to adaptive
incapacitating that salvage of the horse is frequently not possible. remodeling from exercise but more likely due to some

A B
Figure 5.84. Tarsal radiograph (A; arrow) and CT (B) demonstrating a slab fracture of the central tarsal bone. These slab fractures occur
most often in horses used for racing disciplines and other high‐speed events.