Normal ultrasonographic anatomy and injury of the patellar ligaments in the horse.

The research article explores the results of ultrasound examinations of the patellar ligaments in healthy horses, and describes clinical characteristics, diagnosis, and outcomes of patellar ligament injury in horses.

Ultrasonographic Analysis of Healthy Horses

• The investigators studied the appearance of patellar ligaments in clinically normal horses using ultrasound. They analyzed the medial, middle, and lateral patellar ligaments of 5 Thoroughbred and 5 Warmblood horses.
• They found the ligaments to be uniform in their echogenicity, which indicates a consistent composition throughout. Also, each ligament had a fairly stable shape across different horses.
• Size differences were noticed between the Warmblood and Thoroughbred horses’ ligaments. The Warmbloods, which are typically heavier, had larger ligaments than the lighter Thoroughbreds.
• The insertion points of these ligaments on the patella and tibia were found to be smooth, suggesting healthy bone-ligament interfaces.

Injuries of the Patellar Ligaments

• Nine horses, mostly showjumpers, were found to have a single hindlimb lameness associated with ultrasound evidence of damage to one or more patellar ligaments.
• Key conditions identified included primary desmitis of the middle patellar ligament (inflammation of ligament) in four horses. One of these also had intermittent upward fixation of the patella, and another had irregular movement of the patella.
• Two further horses had inflammation of the middle patellar ligament associated with a previous medial patellar desmotomy (surgical cutting of the ligament).
• Two horses presented inflammation of the middle and lateral patellar ligaments, while one horse had the same condition in the lateral patellar ligament alone.
• Of the nine horses, none could consistently return to their former competition level post-injury, indicating the severity of patellar ligament damage.

Recommendations for Diagnosis

• The study emphasizes the value of careful clinical evaluations and ultrasonographic examinations for horses showing hindlimb lameness of unclear cause. The findings reinforce understanding and diagnosing injuries to the patellar ligaments as it may significantly impact the performance potential of the horses.