Stifle Joint Injuries: Diagnosis, Treatment and Prognosis
Horses can present with developmental or athletic use injuries to their stifles including bone, cartilage, ligament and synovial structures. Soft tissue injuries, that are not effectively treated, can lead to chronic joint instability and to secondary arthritis.
As in all ultrasound examinations, the imaging portion of the examination should be used to confirm suspect injuries based on a thorough clinical examination. For example, horses that have intermittent upward fixation of the patella are suspect for medial patellar ligament desmitis. These horses are generally not lame or mildly so. They tend to have femoropatellar joint effusion that is mild. Horses with collateral ligament and meniscal injuries are initially Grade II-III/V lame and positive to flexion. There is generally moderate to marked femorotibial joint effusion. As 75% of meniscal injuries are to the medial meniscus and to the medial collateral or meniscotibial ligaments, clinical signs will usually be most prominent on the medial aspect of the limb.
Ultrasound is more sensitive than radiography at detecting bony changes such as femoral trochlear ridge DOD. Young horses beginning training that have stifle-based lameness and effusion of the femoropatellar or femerotibial joints, are suspect for DOD and need an ultrasound examination, especially in the absence of radiographic changes. Ultrasound is also more sensitive than radiography at detecting early femoral or tibial changes associated with meniscal injury.
The image above is of the cartilage and underlying bone of a segment of normal lateral trochlear ridge.