Abstract
Objective
This study aimed to systematically investigate the ototoxic potential of cobalt in patients with a metal-on-metal (MoM) hip implant, using objective auditory and vestibular assessments and a questionnaire. The results of the objective evaluation were published previously, whereas the current study focused on the questionnaire outcome and its relationship to the blood cobalt level.
Design and study sample: Twenty patients (33–65 years) with a primary MoM hip implant and 20 non-implanted control subjects, matched for age, gender, and noise exposure, received a questionnaire to evaluate the presence of several hearing and balance symptoms (part 1) and general neurological issues (part 2).
Results
Concerning part 1, the proportion of auditory-related symptoms in general (p = 0.022) and tinnitus (p = 0.047) was significantly higher in the MoM patient group, whereas no group difference was found for hyperacusis, increased listening effort, and decreased speech understanding. Concerning part 2, no significant group differences were detected. Within the MoM patient group, the questionnaire outcome was not significantly different between the low-exposure and high-exposure subgroups according to the blood Co level.
Conclusions
In line with our previous study, these results potentially imply Co-induced impairment to the auditory system, despite the lack of a clear dose–response relationship.
Acknowledgements
The authors thank Dr. Koen De Smet and Bart De Roest from the ANCA hip clinic (Ghent, Sint-Martens-Latem) for the assistance in the recruitment of patients with a metal-on-metal hip implant.
Disclosure statement
No potential conflict of interest was reported by the author(s).