Title : Hypoallergenic knee implant usage and clinical outcomes: Are they safe and effective
Abstract:
Background: Total knee arthroplasty (TKA) is a commonly performed treatment with excellent clinical effectiveness. Metal hypersensitivity (MH) is a newly proposed theory that leads to the failure of TKA. Our systemic review aims to summarise the latest findings and to identify the gaps and barriers in the current field to guide future research.
Methods: The literature search was conducted on PUBMED, MEDLINE, and Google Scholar, including all full manuscripts reporting the clinical outcomes of hypoallergenic TKA in the English language from July 2018 to July 2023.
Results: Clinically, MH is a diagnosis of exclusion, after the common reasons for TKA failure, such as infection and aseptic loosening, have been ruled out.
Several retrospective studies and two randomized control studies demonstrated equally good clinical outcomes of hypoallergenic TKA and standard metal implants.
In suspected or confirmed MH-induced implant failure, the patients underwent revision TKA (rTKA) with hypoallergenic implants. Overall improvements in patients’ symptoms and clinical outcomes at short-to-medium-term follow-up were reported. Those who had a revision with standard implants or were not revised continued to display inferior clinical presentations.
Conclusion: The results from our systemic review showed comparable clinical values of hypoallergenic implants to traditional metal implants, with similar survival and complication rates. In rTKA, both types of hypoallergenic prostheses have demonstrated similar effectiveness in improving patients’ symptoms and maintaining long-term benefits. Nonetheless, there is no clear evidence of the association between pre-operative MH testing and the clinical outcomes in TKA patients. And the theoretical benefits of hypoallergenic implants need to be further investigated to make the manufacturing costs clinically justifiable.
