Verification of palpation-guided intra-articular injections using glucocorticoid-air-saline mixture and ultrasound imaging (GAS-graphy).

OBJECTIVE To examine a contrast medium method using a glucocorticoid-air-saline mixture and ultrasound imaging (GAS-graphy) for the verification of palpation-guided injections in different joints and to assess the inter-reader reliability of the method. METHODS A palpation-guided injection of an air-steroid-saline mixture was given into a joint or tendon sheath of 133 consecutive patients. The dynamic ultrasound monitor images of the joints and tendons involved were videotaped before and after the injection. A rheumatologist and two radiologists analyzed separately the video clips of each patient, under blinded conditions. The readers evaluated the accuracy of the injections and the difficulty of the reading process. The inter-reader agreement was assessed by calculating the percentual values and overall kappa coefficient between the readers. RESULTS The overall accuracy of the successful injections was 76%, 80% and 82 % evaluated by the three readers. In six out of the ten injection sites the accuracy was higher than 80%. The clarity of the method evaluated by the readers was 8, 8 and 8.5 on a scale from 0 to 10. The inter-reader agreement assessed by percentual values was 84.2%, 85.0% and 88.7%. The kappa coefficient between all readers was 0.595 showing moderate agreement. CONCLUSION The GAS-graphy method for the verification of palpation-guided injections is a simple procedure performable to any joint site and the result can be seen immediately on the monitor after the injection. The reliability of the method is good and it can be used in developing injection techniques as well as in medical or nurse education. The method can be used as an alternative for the radiographic contrast medium method in verifying successful palpation-guided intra-articular injections.