Page 403 - The Veterinary Care of the Horse
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Figure 8.24 Upward fixation of the patella
In some horses and ponies, the limb does not lock but tends to ‘catch’ with every stride. This
is known as ‘delayed patella release’. It is most noticeable if the horse is observed walking
downhill or turned in a short circle with the affected limb on the inside. It may be seen when
the horse turns round in the stable or walks forwards after standing still. It may also be
observed on the downward transition from trot to walk or seen if the horse is standing square
and rocked from side to side.
The condition does not usually cause lameness, but the femoropatellar joint may become
distended due to inflammation of the synovial membrane in longstanding cases. These horses
may find walking downhill very uncomfortable and be unhappy working in deep going.
DIAGNOSIS
Diagnosis is made on the history and the clinical signs but can be difficult in horses where
the condition occurs only intermittently. Radiographs of the stifle may be taken to eliminate
joint pathology such as osteochondrosis. Ultrasonography is used to assess the soft tissues.
TREATMENT
• The first line of treatment is to increase the fitness of the affected animal and improve its
