Page 231 - Equine Clinical Medicine, Surgery and Reproduction, 2nd Edition

206 CHAPTER 1

VetBooks.ir 1.394 Aetiology/pathophysiology
The aetiology of chondromalacia as a primary con-
dition is currently unknown. When it is seen in
combination with soft-tissue pathology, it is assumed
to have either arisen from the same injurious inci-
dent or to have occurred as a result of an altered joint
environment.

Clinical presentation
Horses affected by chondromalacia may demonstrate
overt unilateral or bilateral lameness or, particularly
where lesions are bilateral, the presentation may be
more one of poor performance. Lameness may be
more apparent in ridden work and may be sudden
or insidious in onset. Palpable effusion of the medial
femorotibial joint is commonly found.

Fig. 1.394 Arthroscopic image of the left lateral
femorotibial joint of a 12-year-old dressage horse in Differential diagnosis
which a tear of the cranial cruciate ligament was found. Soft-tissue injuries of the medial femorotibial joint;
OCD; OCLLs of the medial femoral condyle.

articular cartilage, further deteriorate the prognosis. Diagnosis
Meniscal tears can be graded from 1 to 3 depending In horses that are overtly lame, a positive response
on severity. Studies have shown that approximately is expected to diagnostic analgesia of the medial
63% of horses affected by grade 1 tears, 56% of femorotibial joint. In horses where lameness is
horses affected by grade 2 tears and only 6% of horses subtle and bilateral, diagnostic analgesia may still
affected by grade 3 tears return to athletic function. be attempted, with increasing lameness in the con-
Horses with desmitis of the patellar ligaments or tralateral limb indicative of a positive response.
damaged collateral ligaments should be treated with Radiography is useful to identify concurrent bony
rest and controlled exercise, and the progress moni- pathology and, in the author’s experience, chondro-
tored ultrasonographically. Some cases have been malacia is more common in horses with a flattened
treated with shockwave therapy. The prognosis for or concave medial femoral condyle on a caudocranial
collateral ligament injury is poor, and some horses projection (Fig. 1.395). Ultrasonography is likely to
with desmitis of the patellar ligament may not return demonstrate effusion and synovial proliferation and
to their previous level of exercise. possibly abnormal cartilage when the medial femoral
condyle is visualised with the limb in a flexed posi-
CHONDROMALACIA OF THE tion. Diagnostic arthroscopy is currently the only
MEDIAL FEMORAL CONDYLE way to reliably assess articular cartilage of the medial
femoral condyle (Fig. 1.396) and may be required to
Definition/overview provide a definitive diagnosis and exclude concur-
Abnormal, soft, fissured, poorly adherent cartilage rent soft-tissue injuries.
over the medial femoral condyle is well recognised
by arthroscopic surgeons. Such cartilage can be seen Management
in isolation or in combination with other injuries In the first instance, and where lameness is mild,
and there is still a debate about whether chondroma- affected horses should be treated with intra-articular
lacia is a primary cause of lameness. corticosteroid medication (5–10 mg triamcinolone