Elsevier

The Journal of Arthroplasty

Volume 31, Issue 8, August 2016, Pages 1717-1721
The Journal of Arthroplasty

Primary Arthroplasty
No Increased Risk of Knee Arthroplasty Failure in Patients With Positive Skin Patch Testing for Metal Hypersensitivity: A Matched Cohort Study

https://doi.org/10.1016/j.arth.2016.01.024Get rights and content

Abstract

Background

It is unclear whether a positive skin patch test for metal allergy in patients with skin hypersensitivity to metals is associated with an increased risk of total knee arthroplasty (TKA) failure. Our aim was to determine whether patients with a history of metal allergy who had a positive skin patch test (SPT+) had worse outcomes after primary TKA compared with those with a negative skin patch test and compared with controls.

Methods

Over 12 years, 127 patients underwent 161 TKA after skin patch testing (SPT; 56 were positive). Cases were matched by age, gender, body mass index, American Society of Anesthesiologists score, implant type, and implant manufacturer to 161 control knee arthroplasties without any prior history of metal allergy and no SPT. Median follow-up was 5.3 years. Differences in outcome measures were assessed between groups.

Results

Patients with a SPT+ to metal did not have a higher complication, reoperation, or revision rates compared with patients with a SPT− and matched controls. Survivorship free of revision at 5 years was 98.1% for SPT+; 100% for SPT−; 97.6% for SPT+ controls, 99.0% for SPT− controls. There was no statistically significant difference in postoperative pain between SPT+ and SPT− patients and matched controls.

Conclusion

This study was designed to evaluate the effect of metal hypersensitivity on TKA outcomes and the role of SPT in patients before TKA. In this study, a SPT+ for metals was of little practical value in predicting the midterm outcome after TKA and cannot be strongly recommended as a method to guide the selection of implant type.

Section snippets

Materials and Methods

We reviewed all TKAs performed at 1 institution between 1997 and 2009. Within this period, 127 patients underwent 161 knee arthroplasties after SPT for a described history of metal allergy. These patients were initially identified by cross-referencing the Mayo Clinic total joint registry and the Mayo Clinic dermatology skin patch test database. The most common metal alloys used in orthopedic surgery are cobalt-chromium, stainless steel, and titanium-aluminum-vanadium alloys [6]. A SPT was

Results

Patients with a preoperative SPT+ to metals did not have a higher complication rate as compared to SPT− patients or compared to matched controls as shown in Table 2 for arthrofibrosis and for instability. There was a statistically significant difference in survivorship free from arthrofibrosis between SPT− and SPT− controls, with a lower survivorship seen in patients who carried a diagnosis of metal allergy but tested negative for it based on a SPT− results.

Patients with a preoperative SPT+ did

Discussion

It is not known whether a SPT+ for metal hypersensitivity is associated with higher failure rates after TKA. The objective of this article is to report the complications, reoperation, revisions, and functional outcomes of TKA in patients with SPT+ for metal hypersensitivity compared to SPT− and a matched control group. This article did not show any significant differences in outcomes between these groups, negating the association between a SPT+ and the results of TKA.

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Acknowledgments

The authors recognize Ana I. Velazquez, MD, for her help with this study.

References (15)

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    Citation Excerpt :

    Studies reporting clinical outcomes after TKAs with hypoallergenic implants for confirmed or suspected metal hypersensitivities have produced conflicting data [5,12–14,17–19]. Patients with hypersensitivity confirmed by contact SPT have been shown to have equivalent outcomes to patients with negative SPT receiving the same TKA implants [14]. Hypersensitive patients have also been shown to do worse after TKAs even if hypoallergenic implants were used [13,17].

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One or more of the authors of this paper have disclosed potential or pertinent conflicts of interest, which may include receipt of payment, either direct or indirect, institutional support, or association with an entity in the biomedical field which may be perceived to have potential conflict of interest with this work. For full disclosure statements refer to http://dx.doi.org/10.1016/j.arth.2016.01.024.

Each author certifies that his or her institution approved the reporting of this study and all investigations were conducted in conformity with ethical principles of research. The Mayo Clinic Institutional Review Board has approved this study, and consent from all patients was granted. This work was performed at Mayo Clinic Rochester, MN.

No external source of funding played a role in the investigation.

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