To date, there have been few reports of the results of revisions for failed metal-on-metal hip arthroplasties (MoM HA's). These series have included relatively modest numbers, and classification of the severity of adverse local tissue reaction (ALTR) has been under-reported. In this study, early outcomes and complications are analyzed as a function of pre-operative MRI grade and intra-operative ALTR severity to determine their prognostic value. This is a retrospective review of revisions of 121 failed MoM HA's performed between 2008 and 2012. Indications for revision include ALTR (n = 97), loose cup (n = 13), and combined loose cup and ALTR (n = 11). When pre-operative MRI's were available, these were graded according to Anderson's system by 2 radiologists who were blinded to the clinical results. Intra-operative findings were graded for severity according to an ALTR classification. Post-operative complications were recorded. Correlations between pre-operative MRI grade, intra-operative ALTR classification and post-operative complications were analyzed using Spearman's rank correlation. ALTR Classification: Type 0: No abnormal fluid or pseudotumor. Peri-articular structures intact. Type 1: Abnormal fluid and/or pseudotumor. Peri-articular structures disrupted but repairable. Type 2: Abnormal fluid and/or pseudotumor. Peri-articular structures disrupted and no meaningful repair possible. Type 3: Abnormal fluid and/or pseudotumor. Peri-articular structrues disrupted, no meaningful repair possible, AND significant necrosis involving abductor muscles.Introduction:
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