Metal hypersensitivity in patients with orthopaedic implant complications-A retrospective clinical study.

BACKGROUND: Hypersensitivity to metals as a cause of implant-related complications has been a subject of controversy. Projections indicate an increase in the frequency of joint replacements of between 300% and 600% by the year 2030; therefore, this issue is of considerable interest.

OBJECTIVE: To evaluate sensitization to implant materials in patients with implant-related complications, to identify allergens, and to clarify whether hypersensitivity is a relevant cause.

METHODS: Patients with implant-related complications or a positive history of contact allergy and planned total joint replacements referred for allergological investigation between 2004 and 2017 were retrospectively analysed.

RESULTS: In total, 311 patients were included. A positive patch test reaction to a metal was seen in 64.4% of preoperative patients and in 54.6% of patients with implant-related complications. Common alloy metals such as cobalt, chromium and titanium gave positive reactions in up to 2.9% of patients with implant-related complications. None of the patients with skin changes had a positive patch test reaction to an implant metal.

CONCLUSION: Other factors, such as the type of replaced joint and mechanical stress, seem to be more relevant for implant-related complications. Sensitization to metals or other materials seems to rarely play a role, and is overestimated.