Page 223 - Equine Clinical Medicine, Surgery and Reproduction, 2nd Edition

198 CHAPTER 1

Foals affected with luxation of the patella are Diagnosis
VetBooks.ir unable to extend the stifle and stand in a charac- Diagnosis is based on clinical signs, palpation and

teristic crouching position (see p. 45). Less severe
nial, and caudocranial oblique radiographs of the
luxation may be manifested as a stiff gait and imaging findings, including lateromedial, caudocra-
refusal to flex the affected limb. Effusion of the stifle region. Careful palpation of foals with patel-
femoropatellar joint is common with fractures of lar luxation reveals the position of the patella, the
the patella, fragmentation of the apex of the patella possibility for relocation and if the luxation is inter-
and all chronic conditions that may promote OA. mittent or permanent. It is extremely important to
Horses that develop fragmentation of the apex of include a cranioproximal/craniodistal (skyline) view
the patella after desmotomy of the medial patel- of the patella if a fracture is suspected (Figs. 1.379,
lar ligament may have excessive fibrous tissue at 1.380), as this may be the only view demonstrating
the surgical site and resent flexion of the affected the fracture line. Ultrasonography is useful for dem-
limb. onstrating excessive scar tissue after desmotomy.

Differential diagnosis Management/prognosis
Stringhalt; fibrous or ossifying myopathy; OCD; Upward fixation of the patella should initially be
septic arthritis; meniscal and/or cruciate ligament treated conservatively with efforts made to increase
tear; desmitis of the patellar ligaments; fracture of muscle mass over the hindquarters through exercise
any other bony component of the stifle; low-grade and improved nutrition. It is important to ensure that
hindlimb ataxia. intestinal parasites are eradicated. In some cases, stifle

1.379 1.380

Figs. 1.379, 1.380 Lateromedial (1.379) and cranioproximal/craniodistal oblique (skyline) (1.380)
radiographs of the stifle demonstrating a sagittal fracture of the medial pole of the patella. Note that the
fracture is more difficult to identify on the lateromedial view.