Page 194 - Equine Clinical Medicine, Surgery and Reproduction, 2nd Edition

Musculoskeletal system: 1.4 The forelimb 169

VetBooks.ir these lesions is usually determined through ruling 1.322 Ia Ib
out other causes of lameness.

Management
Enostosis-like lesions appear to be self-limiting and
cases are usually managed conservatively.

Prognosis
Recurrence may occur. Some studies show the likeli-
hood of racing decreases with increasing number of
enostosis-like lesions, whereas other studies show no
long-term effect on outcome.

ULNA FRACTURES II III

Definition/overview
Fractures of the proximal ulna involving the olecranon.

Aetiology/pathophysiology
Ulna fractures are common. Most cases are due to direct
trauma (e.g. kick) or impact at speed. There are five
main types of fracture configuration described with or
without articular involvement (Fig. 1.322 and Table 1.3).

Clinical presentation IV V
Lameness in horses with an ulna fracture is usually
severe as they are unwilling to extend the elbow and
therefore stand with the elbow dropped and carpus
flexed (Fig. 1.323). Palpation and manipulation of
the elbow region is resented and there is usually soft-
tissue swelling, with or without a wound present.

Differential diagnosis
Humeral fracture; radial nerve paralysis; elbow luxa-
tion; synovial sepsis. Fig. 1.322 Schematic diagram of proximal ulna
fracture classification. (See Table 1.3 for description.)

Table 1.3 Classification of ulna fractures

TYPE DESCRIPTION
Ia Non-articular fracture involving separation of the proximal ulnar physis. Seen in young foals.
Ib Articular fracture through the proximal ulnar physis and metaphysis, entering the joint near to the anconeal process. Seen in
older foals.
II Simple transverse fracture entering the elbow joint at the mid-point of the trochlear notch.
III Non-articular fracture across the olecranon, proximal to the anconeal process.
IV Comminuted, articular fracture.
V Distal caudal fracture of the olecranon/ulnar shaft, traversing proximally and cranially to enter the distal aspect of the
trochlear notch.