Cookies on this website
We use cookies to ensure that we give you the best experience on our website. If you click 'Continue' we'll assume that you are happy to receive all cookies and you won't see this message again. Click 'Find out more' for information on how to change your cookie settings.

Background and purposeMetal artifact reduction sequence (MARS) MRI and ultrasound scanning (USS) can both be used to detect pseudotumors, abductor muscle atrophy, and tendinous pathology in patients with painful metal-on-metal (MOM) hip arthroplasty. We wanted to determine the diagnostic test characteristics of USS using MARS MRI as a reference for detection of pseudotumors and muscle atrophy. PatienTS AND METHODS: We performed a prospective cohort study to compare MARS MRI and USS findings in 19 consecutive patients with unilateral MOM hips. Protocolized USS was performed by consultant musculoskeletal radiologists who were blinded regarding clinical details. Reports were independently compared with MARS MRI, the imaging gold standard, to calculate predictive values.ResultsThe prevalence of pseudotumors on MARS MRI was 68% (95% CI: 43-87) and on USS it was 53% (CI: 29-76). The sensitivity of USS in detecting pseudotumors was 69% (CI 39-91) and the specificity was 83% (CI: 36-97). The sensitivity of detection of abductor muscle atrophy was 47% (CI: 24-71). In addition, joint effusion was detected in 10 cases by USS and none were seen by MARS MRI.InterpretationWe found a poor agreement between USS and MARS MRI. USS was inferior to MARS MRI for detection of pseudotumors and muscle atrophy, but it was superior for detection of joint effusion and tendinous pathologies. MARS MRI is more advantageous than USS for practical reasons, including preoperative planning and longitudinal comparison.

Original publication

DOI

10.3109/17453674.2014.908345

Type

Journal article

Journal

Acta orthopaedica

Publication Date

08/2014

Volume

85

Pages

375 - 382

Addresses

Institute of Orthopedic and Musculoskeletal Science , University College London, the Royal National Orthopedic Hospital, Brockley Hill , Stanmore.

Keywords

Humans, Femur Head Necrosis, Arthralgia, Osteoarthritis, Hip, Muscular Atrophy, Granuloma, Plasma Cell, Postoperative Complications, Metals, Magnetic Resonance Imaging, Ultrasonography, Arthroplasty, Replacement, Hip, Reoperation, Artifacts, Sensitivity and Specificity, Prospective Studies, Reproducibility of Results, Aged, Middle Aged, Female, Male