Ultrasound: Optimal screening test for pseudotumor detection

Since 1990, metal-on-metal (MOM) hip arthroplasties have been increasingly used. However, there have been concerns lately regarding adverse local tissue reaction to metal ions leading to aseptic masses called pseudotumors. Ultrasound (US), computerized tomography (CT), and magnetic resonance imaging (MRI) have all been suggested to investigate this problem. We have reviewed the use of ultrasound in the detection of pseudotumors and have found it to be equally sensitive and specific, easily accessible, and not as affected by metal artifacts compared to MRI. We recommend that ultrasound be considered as the first line of investigation to rule out a pseudotumor formation in MOM hip arthroplasties.