Introduction
Ultrasonographic evaluation of the equine stifle has dramatically increased our knowledge of stifle soft tissue injuries over the past 10-15 years, including patellar ligament, meniscal and cranial meniscal ligament injuries.1-7 Indications for ultrasound include lameness localized to the stifle joint, effusion and radiographic findings of osteoarthritis that may indicate joint instability. Ultrasound is also indicated in horses with wounds to rule out concurrent soft tissue injury or to detect evidence of sepsis. Ultrasound can be useful to detect osteochondrosis lesions of the trochlear ridges in juvenile horses that are normal radiographically.8 Ultrasound may be indicated in horses with radiographically visible OCD lesions when lameness is more severe than would be expected with an OCD lesion.
Summary
It is hoped that this proceedings will serve as a useful guide and resource for future stifle scans. Ultrasound of the stifle can be a challenging but rewarding experience, made easier by a strong knowledge of stifle anatomy. It is not a coincidence that some of the best imagers in the world are either anatomists or have an exceptional knowledge of anatomy. Stifle ultrasonography takes considerable practice and will not be mastered after a few cases. Some horses are more difficult to scan than others, especially those with chronic stifle problems and significant effusion/synovitis. Novice ultrasonographers should begin with the most straightforward structures to scan (patellar ligaments and medial meniscus) and then progress to the more difficult structures.
