The Journal of Arthroplasty, Volume 31, Issue 9, 1910 - 1915

Patient-Reported Metal Allergy: A Risk Factor for Poor Outcomes After Total Joint Arthroplasty?

Nam, Denis et al.
Hip Knee

Background

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).

Methods

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.

Results

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).

Conclusion

Patient-reported metal allergy is associated with decreased functional outcomes after TKA and decreased mental health scores after THA.


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