OBJECTIVES

In dogs, the stifle is the most frequently injured joint, being ligamentous and meniscal injuries the most common, associated with secondary degenerative changes. Diagnosis of stifle joint disorders is generally based on history of lameness, physical examination, radiography, exploratory surgery, arthroscopy, arthrography, ultrasonography and magnetic resonance imaging. Canine arthrography of this joint has received little attention in the veterinary literature. At the present, there are some contrast media that induce less synovial irritation and improve the image quality. The objective of this study was to evaluate arthrographic quality and synovial inflammatory response using iohexol as contrast medium in dogs.

MATERIALS

The study was carry out in 12 healthy dogs divided in 2 groups, medium, 10-15 kg. and large dogs,20-30 kg. No abnormalities were found on physical and radiographic examination of the dogs prior the arthrographic study. Arthrograms were performed under general anaesthesia. Iohexol was administrated at dose of 0.4 ml/cm mediolateral joint width and 300 mgI/ml. The injection was noted as time zero. Standard mediolateral and caudocranial radiographic views were made. Radiographs were taking at 0, 3, 5, 10, 15, 20 and 30 minutes after injection. Synovial fluid was collected for cytologic analysis from each joint immediately before contrast medium was injected and at 1, 3 and 7 days after injection. Another sample of synovial fluid was taken from each contralateral joint at the same time to use it as control.

Images were considered as acceptable or unacceptable, evaluating the overall impression of the quality of the contrast material of the arthrogram, and the joint space opacification. On the acceptable images, both cruciate ligaments, the tendon of the long digital extensor muscle, the suprapatellar bursa, the outline of the infrapatellar fat pad, joint capsule, the menisci, and the delineation of the articular cartilage surfaces of the femoral condyles were evaluated, scores were ranged from 0 to 3 (0= not discernible, 1= visible but not accessible for radiographic evaluation, 2= distinct and eventually accessible for radiographic evaluation, 3= obvious and clearly outlined, perfectly accessible for radiographic evaluation).

RESULTS

Of 12 arthrograms, 11 (91,6%) were classified as acceptable. Radiographs made within 10 and 15 minutes after injection produced diagnostic arthrograms with delineation of the intracapsular structures. The cranial cruciate ligament, the tendon of the long digital extensor muscle, the suprapatellar bursa and of the articular cartilage surfaces of the femoral condyles were classified as obvious and clearly outlined and perfectly accessible for radiographic evaluation, meanwhile the rest of the articular structures were visualized being distinct and eventually accessible for radiographic evaluation. It wasn't found any significant difference between the groups. The day after the examination none of dogs showed any signs of lameness. All synovial fluid samples collected 1 and 3 days after the arthrographies were turbid with increase in WBC. All samples collected 7 days after all arthrographic procedures were clear, colorless and with cytologic values remained within normal limits in all dogs.

CONCLUSION

Arthrography performed with iohexol, does not provide a full anatomic detail of all structures of the stifle joint in dogs, although some articular structures as the cranial cruciate ligament, the tendon of the long digital extensor muscle, the suprapatellar bursa and the articular cartilage surfaces of the femoral condyles could be perfectly accessible for radiographic evaluation. No inflammatory changes in the synovial fluid 7 days following injection of iohexol was observed.