Abstract: Due to the long service duration time and less inflammatory osteolysis, hard-on-hard artificial joints, such as ceramic-on-ceramic or metal-on-metal joints, are considered more suitable for young and active patients. However, the incidence of squeaking associated with hard-on-hard bearings is variably reported, ranging from 0.7% to 20.9%. Since squeaking is a tribological induced acoustics emission phenomenon, contributing factors may include material friction and wear, loss of lubrication, component malposition, edge loading and impingement. A new biotribologicial and acoustic test methodology is proposed. Testing system, including an artificial joint material tribometer, acoustic acquisition system and a simu-anechoic chamber, is developed for the biotribo-acoustic tests of hard-on-hard artificial joint material. Tribological and acoustic data are acquired on-line synchronously. Via this system, ZrO2 on ZrO2 ceramic artificial joint materials tests are performed under the lubrication of deionized water and biomimetic synovial fluids. Results show that in BSF, both friction coefficient and sound pressure are lower than those in the deionized water. Moreover, film lubrication is provided by the BSF, wear surfaces are much smoother. However, under deionized water lubrication abrasive wear is found. In frequency analysis, the sound frequency observed under BSF lubrication is similar to the clinical squeaking results. Thus, through testing system development and preliminary test validation, a new and effective proposal for biotribo-acoustic methodology for the fundamental study of artificial joint materials is provided.

Key words: Acoustics, Artificial joint, Biomimetic synovial fluid, Biotribology, Squeaking