To develop and assess a stable method for ascertaining the placement of intraarticular injections for osteoarthritis (OA) in the hip and knee.
Injections into the hip or knee joint with e.g. hyaluronan or cortisone were performed under the guidance of ultrasound. For this purpose an Acuson Sequoia apparatus and a 8-15 MHz transducer were used. After perforation of the capsule with a 21 G needle, 0.5-1 ml of atmospheric air and 1 ml lidocain 1% was injected with simultaneous recording of the ultrasound signals. This procedure was undertaken before the injection of the medication through the in situ needle.
In the hip joint the injected air could readily ascertain the placement of the injection with a sharp echoic contrast forming on the ultrasound picture respecting the joint cavity. In the knee joint the procedure gave the best results in joints which have a small amount of fluid in either the suprapatellar bursa or in a pouch regularly observed over the lateral joint margin. However, also in some so-called 'dry' knee joints the air could be traced in the bursa by ultrasound.
By the injection of air, it is possible to test the placement of intraarticular injections in both hip and knee joints. This procedure will give a supplementary documentation of the injection as compared to a mere ultrasonographic demonstration of the position of the needle in the joint. The method is proposed as a tool for both learning purposes and quality assurance in daily therapy.