Page 226 - Equine Clinical Medicine, Surgery and Reproduction, 2nd Edition

Musculoskeletal system: 1.5 The hindlimb 201

VetBooks.ir 1.385

Fig. 1.385 Lateromedial radiograph of a
Swedish Warmblood foal with stifle distension
and lameness. Note the upper third lateral
trochlear ridge and upper subpatellar
osteochondrosis lesions. (Photo courtesy
Graham Munroe)

lateral ridge; irregularity of the contour of the ridge; 1.386
one or more subchondral lucent defects in the ridge
+/– surrounding sclerosis; osseous density fragments
within the ridge defects or free in the joint distally
(Fig. 1.386); irregularity of the articular surface of
the patella towards the apex +/– surrounding sclero-
sis; and evidence of osteophytic development in older
horses with secondary OA. Ultrasonography of the
femoropatellar joint will identify joint distension
and localised trochlear ridge cartilage lesions (see
Chapter 1.2, Figs. 1.85, 1.86). It may also provide
the means to measure the size of any lesion, which
can be useful prognostically. Arthroscopy of the
joint allows identification of all lesions and assess-
ment of the extent of cartilage damage (Fig. 1.387).

Management
In early or mild cases, conservative treatment with
rest, systemic NSAIDs and possibly intra-articular
medications may be adequate to return the animal to
soundness in the short term. Some of these animals
may develop problems later in life due to the onset
of early joint disease and OA. Surgical intervention Fig. 1.386 A 30° caudolateral/craniomedial oblique
using arthroscopy is recommended for most cases but radiograph of the left stifle of a 6-year-old eventer.
particularly those that are lame, have not responded to Osteochondral fragments can be seen associated with the
conservative treatment, have large lesions and where upper third of the lateral trochlear ridge of the femur.
an athletic career is envisaged (Fig. 1.388). Horses
with OA are treated conservatively in most cases.
both limbs are involved. The prognosis is generally
Prognosis guarded to fair for return to athletic soundness for
This depends on the extent and severity of the lesions, lesions requiring surgical intervention and guarded
at what age they are detected and whether one or to poor where OA is evident. The size of the lesion