EQUINE ARTHROGRAPHY

To obtain detailed radiographic information about the joint capsule, joint cavity, or articular cartilage, negative (air), positive, or double contrast arthrography is required. Negative and positive contrast arthrograms are easily obtained in a standing horse. Aseptic technique must be utilized. Aspiration of synovial fluid is followed by injection of contrast medium. For double contrast arthrography the horse must be anesthetized. After removal of some synovial fluid and the injection of air and positive contrast medium with the horse in lateral recumbency, the position of the horse is altered. Use of double contrast arthrography is limited to larger joints. In small joints distribution of air and positive contrast medium will be unequal, resulting in false-positive or false-negative findings. The diagnostic value of negative contrast arthrograms is relatively poor. Such arthrograms are useful only for the visualization of radiolucent joint mice or for the differentiation of intraarticular and extraarticular bone fragments. Positive contrast arthrograms are useful for the detection of larger synovial abnormalities, e.g., villonodular synovitis, herniation, or rupture of the joint capsule, or for the visualization of communication between the joint cavity and cystic bone lesions or cystic periarticular soft tissue masses. Double contrast arthrograms provide more detailed information than negative or positive arthrograms. Minor abnormalities of the articular cartilage or the synovial membrane can be visualized.