Silent soft tissue pathology is common with a modern metal-on-metal hip arthroplasty

Abstract

Background and purposeAdverse reactions to metal debris have been reported to be a cause of pain in metal-on-metal hip arthroplasty. We assessed the incidence of both symptomatic and asymptomatic adverse reactions in a consecutive series of patients with a modern large-head metal-on-metal hip arthroplasty.MethodsWe studied the early clinical results and results of routine metal artifact-reduction MRI screening in a series of 79 large-head metal-on-metal hip arthroplasties (ASR; DePuy, Leeds, UK) in 68 patients. 75 hips were MRI scanned at mean 31 (12–52) months after surgery.Results27 of 75 hips had MRI-detected metal debris-related abnormalities, of which 5 were mild, 18 moderate, and 4 severe. 8 of these hips have been revised, 6 of which were revised for an adverse reaction to metal debris, diagnosed preoperatively with MRI and confirmed histologically. The mean Oxford hip score (OHS) for the whole cohort was 21. It was mean 23 for patients with no MRI-based evidence of adverse reactions and 19 for those with adverse reactions detected by MRI. 6 of 12 patients with a best possible OHS of 12 had MRI-based evidence of an adverse reaction.InterpretationWe have found a high early revision rate with a modern, large-head metal-on-metal hip arthroplasty. MRI-detected adverse rections to metal debris was common and often clinically “silent”. We recommend that patients with this implant should be closely followed up and undergo routine metal artifact-reduction MRI screening.

MRI Predicts ALVAL and Tissue Damage in Metal-on-Metal Hip Arthroplasty

“…These values are a major improvement on the predictive ability of blood cobalt and chromium ion levels for identifying a failing hip implant, which have sensitivity and specificity of 63% and 86%, respectively [9]. Other groups have used MRI to study soft tissue lesions around MOM hip implants, but none has used quantitative, reproducible MRI features and none has compared findings between groups formed on a histologic diagnosis [5,8,11,27,30,35]. In a retrospective study, Toms et al [30] qualitatively graded adverse reactions as mild, moderate, or severe and commented on features such as fluid or solid content and walls of the lesions.…”

Early Lessons From a Worldwide, Multicenter, Followup Study of the Recalled Articular Surface Replacement Hip System

“…Moreover, the location or severity of ALTRs did not affect patient-reported outcome measures. Our study results also add to the growing body of evidence that moderate and even severe ALTRs can be asymptomatic [4,31].…”

“…Several studies have also shown that the survivorship of ASR XL THA is significantly poorer than for ASR resurfacing yet the reason for this is not fully understood [18,24]. Interestingly, some studies have also reported that many ALTRs occur in asymptomatic patients [4,31]; this is cause for concern because patients may present with symptoms only after severe collateral tissue damage has occurred, making reconstructive procedures challenging and outcomes unpredictable [21]. Also, little is known about capsular dehiscence patterns as ALTRs decompress from the hip into the surrounding tissue planes.…”

CORR Insights®: Early Lessons From a Worldwide, Multicenter, Followup Study of the Recalled Articular Surface Replacement Hip System

“…A number of questions also remain regarding imaging: Which approach, ultrasound or MRI, affords the best balance of sensitivity, specificity, and cost-effectiveness? We know from this study and others [2,7] that validated outcomes scores sometimes stay the same whether or not ALTR is present. Therefore, what is the best approach to using validated outcomes scores in patient assessment for this problem?…”