Failure by Immune Reaction to Metal Debris in Total Joint Arthroplasty of Hip and Knee

Background: We propose a clinical classification for Failure by Immune Reaction to Metal debris (FIRM) in Total Joint Arthroplasty (TJA) of hip and knee. We also developed an evidence based diagnostic scoring system and estimated the treatment threshold for FIRM. Methods: Pub Med and Embase search engines were used to identify original articles. We classified FIRM and identified the individual diagnostic criteria for each type of FIRM. For each individual diagnostic criterion we estimated the pooled Diagnostic Odds Ratio (DOR+) and the individual discriminatory FIRM (id FIRM) scores. From these scores total discriminatory FIRM (TdFIRM) scores were calculated. Results: We identified a total of 39 original articles for meta-analysis. Based on predominant symptom of clinical presentation, we classified FIRM in to two types i.e., FIRMtype1 and FIRMtype2. We identified 8 individual diagnostic criteria for FIRMtype1 and FIRMtype2 and for each type we estimated the pooled diagnostic odds ratio (DOR+) and the individual discriminatory FIRM (id FIRM) scores. TdFIRM score scores for FIRMtype1 and FIRMtype2 were 4.83 and 4.85 respectively. Treatment threshold for FIRMtype1 and FIRMtype2 were estimated to be 3.38 and 3.39 respectively. Conclusion: This meta-analysis provides a clinically useful tool for decision making when evaluating a patient suspected to have developed clinical complication by immune reaction to metal debris from arthroplasty. Future studies on FIRM should utilize this scoring system in decision making and critically evaluate its validity.