Page 661 - Adams and Stashak's Lameness in Horses, 7th Edition

Lameness of the Proximal Limb 627

recent study, 27 horses underwent ORIF and 15 sur-
vived to hospital discharge (56%), of which only three
VetBooks.ir adult horses was a result of SSI and resultant construct
were adult horses. Failure in the surgically managed
failure in 13.
78
Displaced closed simple fractures of the radius in
foals have a favorable prognosis. Physeal and transverse
mid‐diaphyseal fractures have an excellent prognosis. In
one report, 2 of 2 foals with Salter–Harris type I and II
proximal physeal fractures and 6 of 7 foals with mid‐
diaphyseal transverse fractures were treated successfully.
Treatment of proximal oblique fractures in 3 of 4 foals
also had an excellent outcome. 72

THE ELBOW
Fractures of the Ulna
Ulna fractures are a relatively common fracture in
younger horses. In a retrospective study of 49 ulnar frac-
tures, 79% occurred in horses less than 2 years of age. 92
Ulnar fractures are classified as types I through VI
(Figure 5.33). Types I and II are Salter–Harris types, frac-
turing through the apophysis of the olecranon tuberosity
in horses that are usually less than a year old. Type I is
more common in neonates, whereas type II is more com-
mon in older foals. The incidence of these fractures is
reduced as this physis closes, starting around 15 months
Figure 5.32. A Salter–Harris type II fracture of the proximal of age. Types III through VI involve the diaphysis of the
radius (arrow). This foal was treated conservatively. olecranon (Figure 5.34). In adults the fractures often
involve the articular surface and are displaced due to
contracture of the triceps apparatus. 19,21,24,92 Displacement
is relative to the level of fracture on the ulna; fractures
Prognosis
distal to the level of the elbow joint have less distraction
Nondisplaced complete and incomplete fractures due to the ligaments between the radius and ulna.
appear to have a good prognosis with conservative
treatment. 7,20,68,78 Stress fractures of the radius are
expected to have a good prognosis if adequately rested, Etiology
similar to reported results of tibial and humeral stress Direct impact or trauma is the most common cause;
fractures. 67 however, in foals, type I and II fractures can occur from
The prognosis for displaced radial fractures depends excessive tensile load of the triceps apparatus. Kick inju-
on the age and weight of the horse, its temperament, and ries appear to be a common cause of ulna fractures in
the fracture type. Although there are a few reports of adults and may be associated with wounds on the lateral
successful treatment of displaced radial fractures with aspect of the elbow.
internal fixation in mature horses, most adult horses
have an unfavorable prognosis for survival regardless of Clinical Signs
the treatment selected. 72,78,90 In one report on 47 cases of
radial fractures, successful treatment (82%) only Fractures of the ulna usually result in an acute non‐
occurred in horses younger than 2 years of age with an weight‐bearing lameness with a classic dropped elbow
overall rate of 64% survival to hospital discharge. In appearance (with the carpus flexed and the horse not
72
the more recent report of 54 cases, the prognosis for bearing any weight on the limb). Nondisplaced fractures
survival to discharge for young horses with open reduc- may initially show the dropped elbow appearance but
tion and internal fixation (ORIF) techniques was good will show progressive weight‐bearing of the limb.
but the converse was true for older horses with negative Varying degrees of soft tissue swelling, crepitation, and
correlations associated with surgical site infection (SSI) skin wounds can be apparent. Limb manipulation is
and increased surgical time (>168 minutes). In one ret- resisted, and efforts to get the horse to load the leg, even
78
rospective study of horses weighing more than 300 kg with a splint in place, are unsuccessful until the triceps
presenting with radial fracture, 9 of 15 were treated apparatus has been repaired.
with internal fixation, and only 2 horses were discharged
from the hospital to resume their former activities. Diagnosis
5
Reasons for nonsurvival included primary implant fail-
ure, infection causing implant failure, and support limb Diagnosis is based upon the appearance of the horse,
laminitis. Comminuted fractures were associated with limb palpation, and radiographs. Differential diagnoses
the highest incidence of fatal complications. In the more may include radial or humeral fractures, radial nerve