The aim of this study was to establish the natural
course of unrevised asymptomatic pseudotumours after metal-on-metal
(MoM) hip resurfacing during a six- to 12-month follow-up period.
We used repeated metal artefact reduction sequence (MARS)-magnetic
resonance imaging (MRI), serum metal ion analysis and clinical examination to
study 14 unrevised hips (mean patient age 52.7 years, 46 to 68,
5 female, 7 male) with a pseudotumour and 23 hips (mean patient
age 52.8 years, 38 to 69, 7 female, 16 male) without a pseudotumour.
The mean post-operative time to the first MARS-MRI scan was 4.3 years
(2.2 to 8.3), and mean time between the first and second MARS-MRI scan
was eight months (6 to 12). At the second MRI scan, the grade of
severity of the pseudotumour had not changed in 35 hips. One new
pseudotumour (Anderson C2 score, moderate) was observed, and one
pseudotumour was downgraded from C2 (moderate) to C1 (mild). In
general, the characteristics of the pseudotumours hardly changed. Repeated MARS-MRI scans within one year in patients with asymptomatic
pseudotumours after MoM hip resurfacing showed little or no variation.
In 23 patients without pseudotumour, one new asymptomatic pseudotumour
was detected. This is the first longitudinal study on the natural history of
pseudotumours using MARS-MRI scans in hip resurfacing, and mirrors
recent results for 28 mm diameter MoM total hip replacement. Cite this article:
