Titanium implants and type IV hypersensitivity reactions: A systematic literature review

This study investigates titanium (Ti) hypersensitivity in surgical implants, which can cause complications like implant failure and inflammation. The goal is to evaluate diagnostic methods, particularly skin patch testing versus the Memory Lymphocyte Immunostimulation Assay (MELISA), to improve outcomes for patients with metal sensitivities. A literature search using databases such as Google Scholar and PubMed identified 18 peer-reviewed studies from 2006 to 2024, focusing on titanium implant reactions. Inclusion criteria involved studies with clinical or experimental data on Ti hypersensitivity, excluding non-metallic implant failures and unrelated hypersensitivity reactions. Titanium hypersensitivity, though rare, can result in chronic inflammation and implant failure in foot and ankle surgeries. Patch testing often fails to detect deep tissue reactions, while MELISA testing shows greater accuracy. Alternative materials, such as ceramic or niobium, may be better for patients with metal allergies. MELISA testing is a more reliable tool for diagnosing metal hypersensitivity than patch testing. Surgeons should consider preoperative MELISA testing and alternative implants to reduce hypersensitivity risks, improving patient outcomes. Preoperative MELISA testing should be standard for titanium implant patients to minimize allergic reactions.