Normal ultrasonographic anatomy and injury of the patellar ligaments in the horse.
Authors: Dyson S J
Journal: Equine veterinary journal
Summary
# Editorial Summary: Patellar Ligament Ultrasonography in the Horse Dyson's 2002 investigation established baseline ultrasonographic criteria for normal patellar ligaments and characterised injury patterns in clinically lame horses, examining the medial, middle and lateral patellar ligaments in ten sound horses (five Thoroughbreds and five Warmbloods) and nine lame horses presenting with hindlimb lameness. Normal ligaments demonstrated uniform echogenicity with consistent individual shape, though Warmblood ligaments were notably larger than Thoroughbred counterparts, reflecting bodyweight differences; bone surfaces at patella and tibial insertions remained smooth. Of the nine affected horses (predominantly showjumpers), primary middle patellar ligament desmitis was most common (four cases), whilst others presented with lateral ligament involvement or concurrent pathologies including intermittent upward fixation of the patella and abnormal patellar tracking; critically, none of the nine horses returned consistently to their previous competitive level. For equine practitioners managing hindlimb lameness of unclear aetiology, particularly in sport horses, systematic ultrasonographic evaluation of the patellar ligaments warrants consideration, as injury to these structures appears associated with significant functional prognosis and should not be overlooked during diagnostic workup.
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Practical Takeaways
- •When evaluating hindlimb lameness with no obvious cause, ultrasound the patellar ligaments—injury is a real possibility and may be the primary diagnosis
- •Middle patellar ligament desmitis is the most common patellar ligament injury and often results in poor athletic prognosis; set realistic expectations with owners
- •Establish baseline ultrasound images of normal patellar ligaments in your practice to improve recognition of subtle changes and early damage
Key Findings
- •Normal patellar ligaments in sound horses show uniform echogenicity with consistent shape, with Warmblood ligaments larger than Thoroughbred ligaments
- •9 horses with hindlimb lameness had ultrasonographic evidence of patellar ligament damage, with middle patellar ligament desmitis being the most common finding (6 of 9 horses)
- •None of the 9 injured horses returned consistently to their former level of competition
- •Ultrasonographic examination of patellar ligaments should be considered in horses with hindlimb lameness of undetermined cause