Evaluation of sound levels in elective orthopaedic theatres during primary hip and knee arthroplasty

Abstract

Background: Orthopaedic surgery involves tools which could cause noise-induced hearing loss in theatre staff. Threshold levels for occupational noise exposure have been developed in the U.K., above which action is required to reduce exposure. The aims of our study were to determine whether equivalent continuous sound pressure levels during elective arthroplasty can be measured using readily available materials, and to assess whether noise exposure levels stand within acceptable occupational noise exposure levels.

Materials and methods: Sound pressure levels of orthopaedic saws were recorded using the MicW i436 connected to an iPhone 4S and the iOS SoundMeter application, and using a professional sound meter. Equivalent sound pressure levels were recorded for total hip replacement (THR) and total knee replacement (TKR) using the MicW i436 SoundMeter application. Data obtained was then used to calculate a "worst case" daily exposure value to assess if sound levels were compliant with U.K.

Results: Sound pressure levels recorded using the MicW i436 and Soundmeter application were accurate compared to professional soundmeter readings. THR showed equivalent sound pressure levels (LAeq) of 77 dBA and TKR showed a LAeq of 80 db. Calculated "worst case" scenarios for daily noise exposure using these values did not meet the lower exposure action values set out by U.K.

Conclusions: It is possible to accurately measure continuous sound pressure levels during elective orthopaedic surgery using readily available materials. Noise exposure values during TKR meet lower exposure action values, and when "worst case" daily exposure levels are calculated this level is still lower than the threshold.

Keywords: Acoustics; Exposure monitoring; Hearing; Noise.