Abstract
This study assesses the incidence of noise in ceramic on ceramic (COC) bearings compared to metal on polyethylene (MOP) bearings. Noise after MOP implants has rarely been studied and they never been linked to squeaking.
We have developed a noise characterising hip questionnaire and sent it along with the Oxford Hip Score (OHS) to 1000 patients; 509 respondents, 282 COC and 227 MOP; median age 63.7 (range 45–92), median follow up 2.9 years (range 6–156 months).
47 (17%) of the COC patients reported noise compared to 19 (8%) of the MOP patients (P=0.048). 9 COC and 4 MOP patients reported their hip noise as squeaking. We found the incidence of squeaking in the COC hips to be 3.2% compared to 1.8% in the MOP hips. Overall, 27% patients with noise reported avoiding recreational activities because of it and patient's with noisy hips scored on average 4 points less in the OHS (COC: P=0.04 and MOP: P =0.007).
This is the first study to report squeaking from MOP hip replacements. We therefore believe the squeaking hip phenomenon is not exclusive to hard bearings. Surprisingly, only a small proportion of patients described nose from their as a ‘squeak’. Noisy hip implants may have social implications, and patients should be aware of this. We have shown a relationship between noise and a lower OHS. However, longer follow-up and further study is needed to link noise to a poorly functioning implant.
