Sonography of joint replacements.

Sonography is ideally suited for the evaluation of joint effusion, synovial thickening, and the ligaments and tendons surrounding a joint replacement because it is not hampered by the dephasing artifact of magnetic resonance imaging or the beam-hardening streak artifact of computed tomographic scanning. Although it is unable to visualize deep within the joint or into the bone surrounding an arthroplasty component, its dynamic capability allows evaluation of joint kinematics and its real-time capability can guide interventional procedures. This article reviews the sonographic appearances of complications of arthroplasty of the shoulder, hip, and knee.