Feasibility of sonography for intra-articular injections in the knee through a medial patellar portal

Objective. The purpose of this study was to investigate the feasibility of using real-time high- resolution sonography to guide an injection needle into the intra-articular space within the knee. Methods. Eighty-nine patients with radiographically confirmed knee osteoarthritis (Kellgren-Lawrence grade 2 or 3) without an effusion were included. After sonographically guided or blind injection of hyaluronic acid (HA) and contrast dye through a medial patellar portal (MPP) into the knee joint, a radiographic image was made to ascertain whether the injected material had reached the intra-articular space. Result. Sonographically guided injections of HA into the knee joint had a significantly greater accuracy rate (95.6%) than blind injections (77.3%; P = .01). Conclusions. Intra-articular injections via an MPP using sonographic guidance may raise the accuracy rate in knee joint injections.