JOA - 2026-05-01 - Journal Article
Metal Hypersensitivity Is Associated With Inferior Implant Survivorship in Total Knee Arthroplasty, but Not Total Hip Arthroplasty: A Large-Database Matched-Cohort Analysis.
Shankar DS, Kubsad S, Hernandez GE, Kahsai EA, Giordani M, Hernandez NM
Topics
Key Takeaway
Preoperative metal hypersensitivity diagnosis is associated with a 3.63-fold increased risk of all-cause TKA revision at 5 years (13.1% vs 3.8%), but confers no significant revision risk increase after THA (4.8% vs 3.0%).
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Summary
This retrospective matched-cohort study used US national claims data (2010–2022) to determine whether a preoperative ICD-coded metal hypersensitivity (MHS) diagnosis predicts implant failure after primary THA or TKA, with 1:4 propensity score matching on age, sex, and CCI. TKA patients with MHS had significantly higher 5-year all-cause revision (13.1% vs 3.8%; HR 3.63), revision for PJI (HR 4.11), and revision for mechanical loosening (HR 4.96) compared to controls. THA patients with MHS showed no significant difference in revision risk versus controls (4.8% vs 3.0%).
Key Limitation
Claims-based MHS diagnosis cannot distinguish true type IV delayed hypersensitivity confirmed by patch testing from nonspecific metal intolerance, creating significant exposure misclassification that likely biases results in an unpredictable direction.
Original Abstract
BACKGROUND
The purpose of this study was to determine if a preoperative diagnosis of metal hypersensitivity (MHS) is a risk factor for worse implant survivorship following total hip arthroplasty (THA) or total knee arthroplasty (TKA).
METHODS
A retrospective cohort study was performed using United States national claims data from January 2010 to October 2022, sourced from a large national database. A cohort of 524 patients undergoing THA and 1,559 patients undergoing TKA who had an MHS diagnosis were 1:4 propensity score-matched to 2,075 THA and 6,189 TKA controls on age, sex, and Charlson comorbidity index (CCI). All patients were ≥18 years old at the time of surgery, underwent primary procedures, and had a minimum 2-year follow-up. Time to revision surgery at up to 5-year follow-up for all causes, for periprosthetic joint infection (PJI), and for mechanical loosening were compared between groups using the Cox proportional hazards model. Hazard ratios (HRs) with 95% confidence intervals were calculated.
RESULTS
For the THA analysis, the 5-year cumulative incidence of revision was low in both groups (MHS 4.8 versus control 3.0%) and there was no significant difference in risk of all-cause revision between groups (P > 0.05). For the TKA analysis, the 5-year cumulative incidence of all-cause revision was high in the MHS group (MHS 13.1 versus control 3.8%), and the MHS group also had a higher risk of all-cause revisions (HR 3.63 [3.00 to 4.39], P < 0.001), revision for PJI (HR 4.11 [2.81 to 6.02], P < 0.001), and revision for mechanical loosening (HR 4.96 [3.82 to 6.46], P < 0.001).
CONCLUSIONS
Preoperative MHS was associated with a higher risk of all-cause revision by 5-year follow-up following TKA, but not THA, though the present study could not establish a causal relationship between MHS and the need for revision surgery.
LEVEL OF EVIDENCE
III, retrospective cohort study.