title: Patient-Reported Metal Allergy: A Risk Factor for Poor Outcomes After Total Joint Arthroplasty?
abstract: Metal sensitivity after total joint arthroplasty has been of increased concern, but the impact of a patient-reported metal allergy on clinical outcomes has not been investigated. The purpose of this study was to report the incidence and impact of patient-reported metal allergy after total knee arthroplasty (TKA) and total hip arthroplasty (THA).
  
  
  
  This was a retrospective, institutional review board-approved investigation of patients undergoing a primary, elective total joint arthroplasty between 2009 and 2011. All patients completed a preoperative questionnaire asking about drug and environmental allergies. In January 2010, a specific question was added regarding the presence of a metal allergy. University of California at Los Angeles Activity, Short Form 12 (SF-12), Modified Harris Hip, and Knee Society scores were collected preoperatively and at most recent follow-up. Overall cohorts of metal allergy and nonmetal allergy patients were compared, and a 1:2 matching analysis was also performed.
  
  
  
  Nine hundred six primary THAs and 589 primary TKAs were included. The incidence of patient-reported metal allergy was 1.7% before January 2010 and 4.0% after (overall 2.3% of THAs and 4.1% of TKAs); 97.8% of metal allergy patients were female. After TKA, postoperative Knee Society Function, Symptoms, Satisfaction, and Expectation scores were all decreased in the metal allergy cohort (P < .001-.002). After THA, metal allergy patients had a decreased postoperative SF-12 Mental Component Score and less incremental improvement in their SF-12 Mental Component Score vs the nonmetal allergy cohort (P < .0001 and P = .001, respectively).
  
  
  
  Patient-reported metal allergy is associated with decreased functional outcomes after TKA and decreased mental health scores after THA.
authors.affiliation: Department of Orthopedic Surgery, Washington University School of Medicine, Barnes-Jewish Hospital, St. Louis, Missouri.
authors.forename: Denis
authors.initials: D
authors.lastname: Nam
authors.affiliation: Department of Orthopedic Surgery, Washington University School of Medicine, Barnes-Jewish Hospital, St. Louis, Missouri.
authors.forename: Kevin
authors.initials: K
authors.lastname: Li
authors.affiliation: Department of Orthopedic Surgery, Washington University School of Medicine, Barnes-Jewish Hospital, St. Louis, Missouri.
authors.forename: Venessa
authors.initials: V
authors.lastname: Riegler
authors.affiliation: Department of Orthopedic Surgery, Washington University School of Medicine, Barnes-Jewish Hospital, St. Louis, Missouri.
authors.forename: Robert L
authors.initials: RL
authors.lastname: Barrack
mesh_terms: D000368:Aged; D019644:Arthroplasty, Replacement, Hip / Q000009:adverse effects*; D019645:Arthroplasty, Replacement, Knee / Q000009:adverse effects*; D005260:Female; D006801:Humans; D006967:Hypersensitivity / Q000150:complications* / Q000453:epidemiology; D015994:Incidence; D007719:Knee Joint; D008297:Male; D008670:Metals / Q000009:adverse effects / Q000276:immunology*; D008875:Middle Aged; D008923:Missouri / Q000453:epidemiology; D011184:Postoperative Period; D012189:Retrospective Studies; D012307:Risk Factors; D011795:Surveys and Questionnaires; D016896:Treatment Outcome
chemical_list: D008670:Metals
keywords: clinical outcomes; metal allergy; patient satisfaction; total hip arthroplasty; total knee arthroplasty