Published online Feb 18, 2019. doi: 10.5312/wjo.v10.i2.63
Peer-review started: October 7, 2018
First decision: October 19, 2018
Revised: December 26, 2018
Accepted: January 5, 2019
Article in press: January 6, 2019
Published online: February 18, 2019
Total knee arthroplasty is a common procedure, with extremely good clinical results. Despite this success, it produces 20% unsatisfactory results. Among the causes of these failures is metal hypersensitivity. Metal sensitization is higher in patients with a knee arthroplasty than in the general population and is even higher in patients undergoing revision surgery. However, a clear correlation between metal sensitization and symptomatic knee after surgery has not been ascertained. Surely, patients with a clear history of metal allergy must be carefully examined through dermatological and laboratory testing before surgery. There is no globally accepted diagnostic algorithm or laboratory test to diagnose metal hypersensitivity or metal reactions. The patch test is the most common test to determine metal hypersensitivity, though presenting some limitations. Several laboratory assays have been developed, with a higher sensitivity compared to patch testing, yet their clinical availability is not widespread, due to high costs and technical complexity. Symptoms of a reaction to metal implants present across a wide spectrum, ranging from pain and cutaneous dermatitis to aseptic loosening of the arthroplasty. However, although cutaneous and systemic hypersensitivity reactions to metals have arisen, thereby increasing concern after joint arthroplasties, allergies against implant materials remain quite rare and not a well-known problem. The aim of the following paper is to provide an overview on diagnosis and management of metal hypersensitivity in patients who undergo a total knee arthroplasty in order clarify its real importance.
Core tip: Metal hypersensitivity may be a cause of failure for total knee arthroplasty, although a clear correlation between metal sensitization and symptomatic knee after surgery has not been ascertained. Patients with a clear history of metal allergy, must be carefully examined through dermatological and laboratory testing before surgery. However, despite the increase in cutaneous and systemic hypersensitivity reactions to metals, which raise concern about joint arthroplasties, allergies against implant materials remain quite rare and an unexplored issue.