CONCISE REPORTS Placement of intra-articular injections verified by mini air-arthrography

Objective—To develop and assess a simple, inexpensive method for ascertaining the placement of intra-articular injections for knee osteoarthritis Methods—During a one year period patients with “dry” osteoarthritis of the knee who received intra-articular therapy were tested by air-arthrography. Along with triamcinolone and lignocaine (lidocaine), 5 ml of air was injected into the joint. On subsequent lateral and anterior-posterior radiographs a correct placement was verified by a sharply defined shadow of air in the suprapatellar pouch, while extraarticular air was diVusely spread in the surrounding tissue. Results—In 51 of 56 cases the injection was correctly placed. In the remaining five cases the injection was immediately repeated and positioned within the joint. No adverse events were seen that could be ascribed to the use of air during the study, although bleeding in the quadriceps was seen one week after an extra-articular injection. Conclusion—With mini-air arthrography, it is possible to test the placement of intra-articular injections in knee joints. The method is proposed as a learning tool as well as providing a means of quality assurance in studies involving intraarticular injections. (Ann Rheum Dis 1999;58:641–643) Some uncertainty has been reported regarding the placement of injections. Arthrography is possible with contrast media, although these have the disadvantage of being rather expensive. Also, this procedure would imply a mixing of several medical substances. Another means of creating a contrast medium for arthrography is by injecting air, which was extensively used in knee joints before the advent of arthroscopy and magnetic resonance imaging. While injected corticosteroids may have some eVect on soft tissue knee pain regardless of intra-articular or peri-articular placement, the glucocorticoid action on the synovium of inflamed joints must be more eVective in the case of a direct, intra-articular placement of the injection. With other kinds of intra-articular therapy, for example, viscosupplementation, ascertaining a correct procedure becomes even more relevant. This study was undertaken to evaluate a simple method of testing the placement of injections for knee osteoarthritis by adding a small volume of air to the injection. Methods Patients with clinical signs and radiological changes of osteoarthritis (Kellgren score of at least two) were included in the study. All patients with “dry” osteoarthritis of the knee were evaluated for the study when referred to the outpatients clinic during the study period. In “dry” osteoarthritis no clinically detectable eVusion was present. An intraarticular injection of corticosteroid was indicated if (1) an acute and not traumatic deterioration of knee pain had not responded to ordinary treatment with analgesics or non-steroidal anti-inflammatory drugs (NSAIDs) and (2) signs of inflammation (other than eVusion) were found, for example, pain along joint margins, or increased skin temperature over the knee. CRITERIA FOR EXCLUSION WERE: EVusion not detected by the clinical examination, but present in aspiration before injection, skin lesions, or infection risks. A total of 56 treatments were given to 38 patients. Six of the patients were treated bilaterally, and during the observation period 15 patients received repeated injections at intervals of at least three months. Of the 38 patients eight were men and 30 women. Mean age was 69 years (range 49–91), and mean duration of osteoarthritis symptoms was seven years (1–40).