ULTRASONOGRAPHIC EVALUATION OF IATROGENIC INJURIES OF THE EQUINE ACCESSORY (CARPAL CHECK) LIGAMENT AND SUPERFICIAL DIGITAL FLEXOR TENDON

Abstract
Iatrogenic lesions to the accessory ligament (carpal check or inferior check) and to the superficial digital flexor tendon of five ponies were monitored utilizing diagnostic ultrasound for a period of 6–24 weeks post‐injury. The opposite limb was used as a non‐surgical control. Sonographic differences from control limbs were recorded and correlated with the gross and microscopic post‐mortem lesions. Early post‐surgical sonographic findings included thickening with discrete hypoechoic areas within the injured tissues which corresponded to regions of hemorrhage, edema, and tissue disruption at necropsy. The linear hyperechoic pattern seen in normal tendons was disorganized in the injured portion of the tendons or ligaments. Disruption of the margins of the incised tissues was observed. The initial hypoechoic areas disappeared or decreased in size and became more echoic as healing progressed. The increasing echoic pattern in these areas corresponded to regions of fibrous tissues invasion and collagen deposition. As post‐injury time increased, the size of the tendon or ligament decreased, the margins became more distinct, and the internal structure again became more organized (linear). It was concluded that diagnostic ultrasound can be useful in evaluating injury and healing of the accessory ligament and the superficial digital flexor tendon of horses.