Sonographically guided injections show more accuracy than blind injections, but there are no reports comparing sonographically guided intra-articular injection approaches. This study examined the accuracy of sonographically guided intra-articular injections at 3 different sites of the knee using medial, midlateral, and superolateral portals.
Sonographically guided intra-articular injections and radiology evaluations were performed on 126 knees with osteoarthritis (Kellgren-Lawrence grade 2 or 3). Six milliliters of mixed material containing 1% lidocaine (1 mL), 20 mg of triamcinolone (1 mL), and a nonionic contrast agent (4 mL) was injected into the intra-articular space of the knee through the medial, midlateral, and superolateral portals. After the sonographically guided intra-articular injection into the knee joint, a radiographic image was taken to determine whether the injected material had reached the intra-articular space or infiltrated into the soft tissue.
Sonographically guided intra-articular injections in the midlateral portal (95%; P < .05) and superolateral portal (100%; P < .05) showed significantly higher accuracy than injections in the medial portal (75%).
Sonographically guided intra-articular injections in the midlateral or superolateral portal may increase the accuracy of knee joint injections.