L. Ly, D. Norris, A. Palmer, B. Tate, R. Nixon
Controversy exists regarding the relevance of metal allergy in patients undergoing prosthetic joint replacements. The relevance of a prior history of metal allergy or skin hypersensitivity (traditionally type IV mediated) in the setting of prosthetic implant failure is unknown and requires clariﬁcation. It is also unclear if a type IV mediated hypersensitivity reaction to metals can actually contribute to implant failure. Theoretically sensitisation and acquired hypersensitivity after surgery in a previously non-sensitised patient is also possible. This is particularly relevant for a large cohort of patients (reported to be 15%) who suffer from residual pain after knee or hip replacement (colloquially termed ‘the unhappy knee or hip’) in which a diagnosis of ‘metal allergy’ is sometimes considered.
We reviewed data from the Contact Allergen Bank Australia of patients referred from orthopaedic surgeons in statewide Victoria for further evaluation of patients with residual pain. To determine the signiﬁcance of metal allergy in this cohort, we reviewed the positive patch test results in these patients and assessed their relevance. Furthermore, we retrospectively analysed the clinical presentations and outcomes associated with a positive reaction to explore the association between metal hypersensitivity and implant failure.