Page 154 - Equine Clinical Medicine, Surgery and Reproduction, 2nd Edition

Musculoskeletal system: 1.4 The forelimb 129

VetBooks.ir 1.225 1.226

Figs. 1.225, 1.226 View of a horse with an acute-onset subluxation of the pastern joint (1.225) and a stressed
view radiograph (1.226) confirming the proximal interphalangeal joint subluxation.

pastern region (Fig. 1.225). Occasionally, horses surgical management through arthrodesis of the
may present acutely lame with soft-tissue swell- pastern joint. Mild cases of dorsal subluxation in
ing but normal anatomical congruity of the joint. young horses are usually managed conservatively.
Presence of avulsion fragments should alert the pos-
sibility of a subluxation having occurred. Prognosis
Prognosis following pastern arthrodesis has a fair to
Differential diagnosis good outcome particularly with involvement of the
P1/P2 fractures; severe soft-tissue injury; synovial hindlimb.
sepsis.
OSTEOARTHRITIS
Diagnosis
Radiography of the pastern will often show the Definition/overview
abnormality present, although stress radiographs OA is a common condition of the pastern joint in
may be required (Fig. 1.226). Ultrasonography of the horse.
the pastern (e.g. distal sesamoidean ligaments) may
be required to assess the integrity of the soft tissues. Aetiology/pathophysiology
OA is a progressive joint condition leading to loss
Management of articular cartilage, subchondral thickening and
Traumatic subluxation can be initially managed osteophyte production. Advanced cases can lead to
through external coaptation. However, ongoing cystic formation and joint collapse with eventual
instability and/or the presence of fractures require ankylosis, although the latter is quite rare. OA may