Page 565 - Adams and Stashak's Lameness in Horses, 7th Edition

Lameness of the Distal Limb 531

Oblique or transverse fractures are uncommon and Selection of the specific treatment method often
do not affect the physis or articular margins. Stabilization depends on the fracture configuration, intended use of
VetBooks.ir sions has been described. Minimally displaced frac- surgeon. If internal fixation is considered, the implants
the horse, economic constraints, and preference of the
of the fracture with lag screws placed through stab inci-
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should permit reapposition of the joint surfaces and
tures may heal with external coaptation. Displaced
fractures usually require open reduction and internal provide longitudinal stability of P1. Internal fixation is
fixation with bone plates. usually recommended in horses with moderately com-
minuted P1 fractures that permit fracture realignment
(Figure 4.111). With severely comminuted fractures,
Comminuted Fractures accurate fracture repair and longitudinal stability is
sometimes impossible.
The objective for treatment of most horses with com-
Horses with an intact cortex (strut of intact fractured
minuted P1 fractures is usually to preserve the horse for P1 that extends from the proximal to distal joint sur-
breeding purposes or pasture soundness. Even horses faces) should be repaired with internal fixation. These
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with only moderately comminuted P1 fractures that are horses have a much greater chance of surviving than
repaired surgically rarely return to racing. In one report, horses without an intact strut of bone. In one study,
zero of 33 Thoroughbred racehorses and 4 of 28 92% of horses with moderately comminuted P1 frac-
Standardbred racehorses returned to racing after sur- tures treated with internal fixation had a successful out-
gery. The goals of surgery are usually to restore the come, whereas horses with severely comminuted P1
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articular congruity of the joint/joints involved and to fractures had a much lower survival rate. The intact
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stabilize the fracture to maintain bone length. Methods strut of bone provides longitudinal stability to the frac-
for treatment of comminuted P1 fractures include:
ture site as well as a solid piece of bone to which frac-
a. External coaptation alone ture fragments can be lagged.
b. External skeletal fixation alone (transfixation pin External skeletal fixation is usually the treatment of
casts or Nunamaker skeletal fixator) choice to repair severely comminuted P1 fractures that
c. Lag screw fixation through stab incisions ± external lack an intact bony strut (Figure 4.112) and for those
skeletal transfixation (Figure 4.111) fractures that are open or have a severely compromised
d. Open reduction with lag screws and external blood supply. 29,35,47,48 External fixation techniques
coaptation reduce the risk of fracture collapse by using transcorti-
e. Open reduction with plates and screws and external cal pins placed in the mid to distal portion of the third
coaptation metacarpus/metatarsus, bypassing weight‐bearing load
f. Reduction combined with transfixation pin casts through the fracture. Most horses should walk comfort-
(Figure 4.112) ably after surgery. Pin loosening, bone sequestration,

A B

Figure 4.111. Lateral (A) and dorsoplantar (B) radiographs that were repaired with multiple lag screws placed through stab incisions.