Comparison of Ultrasound-Guided Intra-Articular Injections by Long Axis in Plane Approach on Three Different Sites of the Knee

OBJECTIVE: The objective of this study was to examine the accuracy of ultrasound-guided intra-articular (IA) injections on three different sites of the knee using midmedial, midlateral, and superolateral portals. DESIGN: Ultrasound-guided IA injection and a radiographic evaluation were performed on 120 knees with osteoarthritis. Five milliliters of a mixed material consisting of 1% lidocaine (1 ml), 20 mg of triamcinolone (1 ml), and nonionic contrast (3 ml) was injected into the IA space of the knee through three different portals. After each injection, a radiographic evaluation was performed to determine whether the injected material had reached the IA space or infiltrated into the soft tissue. RESULTS: Of 40 injections administered through the midmedial portal, 38 were confirmed as having been placed in the IA space on the first attempt (95% accuracy rate). Thirty-nine of 40 injections administered through the midlateral portal were IA on the first attempt (98.5% accuracy rate), as were 40 of 40 injections administered through a superolateral portal (100% accuracy rate). No significant differences (P > 0.05) were observed in the accuracy rate obtained with placement through the midmedial, midlateral, and superolateral portals. CONCLUSIONS: All three ultrasound-guided IA injections may be used to access the knee joint, with a high rate of accuracy.