Cobalt hip implants and auditory-vestibular outcome
Reviewed by Joanna Lemanska

Cobalt-chromium (Co-Cr), metal-to-metal hip implants were commonly used until several side-effects were reported due to an increased level of Co and Cr metal ions in patients’ blood. Although this type of hip replacement was almost completely abandoned, there are still patients with this type of implant. This study is part of the larger pilot research concerning the auditory and vestibular function in patients with a metal-to-metal hip implant and pertains to self-reported auditory, vestibular, and general neurological symptoms in participants with and without hip implants (control group). Each group consisted of 20 participants. All participants were asked to complete questionnaires in order to self-assess their auditory and balance problems. Participants in the test group were asked to concentrate on the post-implementation period while completing the questionnaires. The proportion of participants with auditory-related symptoms and tinnitus were significantly higher in the test group than in the control group. Although the proportion of participants reporting hyperacusis was not significantly different between groups, the authors stressed that increased relative risk in implanted participants and 30% higher proportion participants reporting hyperacusis may indicate that implanted patients may be at risk of developing hyperacusis. The non-significant difference in reference to hyperacusis may be explained by low sample size which led to limited power of the results. There was no significant difference in vestibular symptoms and general neurological symptoms between groups.

The ototoxic potential of cobalt from metal-on-metal hip implants: a pilot study on the patient-reported auditory, vestibular, and general neurological outcome.
Leyssens L, Vinck B, Van Der Straeten C, et al.
INT J AUDIOL
2021;60(1):44-53.