## Overview Upward fixation of the patella occurs when the medial patellar ligament catches over the medial trochlear ridge and cannot release, locking the hind limb in extension. The leg drags behind until it suddenly releases with a jerk or click. It is common in young, unfit horses and those with straight hind-limb conformation. Mild cases are intermittent and worse at the walk or when starting out. Severe cases may remain locked for hours. ## Causes Poor quadriceps tone, straight conformation, or sudden reduction in fitness. ## Diagnosis Observation of intermittent or persistent locking. ## Treatment Conditioning and hill work for mild cases. Medial patellar ligament splitting or desmotomy for persistent cases. ## Recovery and Prognosis Excellent with appropriate management. ## Prevention Maintain fitness, especially in predisposed horses.
hind limb locked in extension; leg drags behind; sudden release with a jerk or click; intermittent in mild cases; worse at walk
## Overview Upward fixation of the patella occurs when the medial patellar ligament catches over the medial trochlear ridge and cannot release, locking the hind limb in extension. The leg drags behind until it suddenly releases with a jerk or click. It is common in young, unfit horses and those with straight hind-limb conformation. Mild cases are intermittent and worse at the walk or when starting out. Severe cases may remain locked for hours. ## Causes Poor quadriceps tone, straight conformation, or sudden reduction in fitness. ## Diagnosis Observation of intermittent or persistent locking. ## Treatment Conditioning and hill work for mild cases. Medial patellar ligament splitting or desmotomy for persistent cases. ## Recovery and Prognosis Excellent with appropriate management. ## Prevention Maintain fitness, especially in predisposed horses.
hind limb locked in extension; leg drags behind; sudden release with a jerk or click; intermittent in mild cases; worse at walk