Ultrasonographic evaluation of tarsocrural joint cartilage in normal adulthorses

Ultrasonographic examination of the tarsus was performed on four clinically and radiographically normal limbs of adult horses. Particular attention wa s paid to the articular cartilage surfaces of the trochlear ridges of the t alus and the distal intermediate ridge of the tibia, Two separate measureme nts of articular cartilage thickness were acquired from a longitudinal view at each site. Anatomy was confirmed with post mortem dissection. Ultrasono graphy was found to be a practical method for imaging the articular cartila ge over the trochlear ridges of the talus and distal intermediate ridge of the tibia, The cartilage appeared as a hypoechoic band overlying the hypere choic subchondral bone. The mean cartilage thickness over the lateral and m edial trochlear ridges of the talus and the distal intermediate ridge of th e tibia were 0.57 mm, 0.58 mm and 0.7 mm respectively. These measurements m ay have value for comparison to thickened cartilage and lesions of osteocho ndrosis and abnormally thinned cartilage of osteoarthritis. Ultrasound exam ination was not helpful in evaluating the proximal and distal intertarsal a nd tarsometatarsal joints, the close proximity of the articular surfaces ob scured visualization of the articular cartilage.