The prevalence of adverse reactions to metal debris (ARMD) associated with metal on metal (MoM) hip arthroplasty has been reported to be as high as 69%. Such findings promoted the development of metal-artefact reducing sequence (MARS)-magnetic resonance imaging (MRI) classifications, with the aim of stratifying soft lesions by severity of disease. The Modified Oxford Classification is a straightforward system that has been shown to correlate with disease progression. The aim of this study was to test the reliability of this classification between observers. Seven observers were recruited, all with a musculoskeletal background. Using the PACS image analysis system, 20 MARS-MRI scans were provided for interpretation. Observers reviewed these scans in random order at two separate intervals over the course of five weeks. They classified them according to the Modified Oxford Classification as: ‘normal’, ‘trochanteric fluid, ‘effusion’, ‘ARMD type 1’, ‘ARMD type 2’ and ‘ARMD type 3’.Introduction
Methods
The prevalence of adverse reactions to metal debris around metal-on-metal (MOM) hip replacements has been reported to range from 7 to 69%. Little has been published on MRI scans with conventional total hip bearing surfaces. This study aimed to establish the prevalence of soft tissue lesions associated with metal-on-polyethylene (MOP) and ceramic-on-ceramic (COC) bearings, compared to MOM prostheses. All Metal Artefact Reduction Sequence (MARS) MRI scans for MOM THRs performed at our unit from January 2009 to present were reviewed, identifying those with contralateral primary MOP or COC THRs included on the scan. These were compared to a previously analysed cohort of 281 MOM THRs. Scans were classified using the Modified Oxford Classification as ‘Normal’, ‘Trochanteric Fluid’, ‘Effusions’ or Adverse Reactions to Debris.Introduction
Patients/Materials & Methods
