Introduction: The lubricant thickness in clearance between bearing surfaces for metallic hip implants are currently incapable of accommodating the motion experienced (high load and low entraining motion) in hip walking cycle. Thus, micro-dimpled surfaces were introduced onto surfaces of metallic acetabular cups to improve lubricant thickness. Micro-dimpled surface is a method of advanced surface improvement to increase the lubricant thickness in various tribological applications, such as hip implants. However, the application of micro-dimpled surfaces in hip implants has not yet been explored adequately. Therefore, this study aims to identify the influence of micro-dimpled depth on lubricant thickness elastohydrodynamically for metallic hip implants using Fluid-Structure Interaction (FSI) approach. Methods: Fluid-Structure Interaction (FSI) approach is an alternative method for analysing characteristics of lubrication in hip implant. Dimples of radius 0.25 mm and various depths of 5μm, 45μm and 100μm were applied on the cup surfaces. The vertical load in z-direction and rotation velocity around y-axes representing the average load and flexion-extension (FE) velocity of hip joint in normal walking were applied on Elastohydrodynamic lubrication (EHL) model. Results: The metallic hip implants with micro-dimpled surfaces provided enhanced lubricant thickness, namely by 6%, compared to non-dimpled surfaces. Furthermore, it was suggested that the shallow depth of micro-dimpled surfaces contributed to the enhancement of lubricant thickness. Conclusion: Micro-dimpled surfaces application was effective to improve tribological performances, especially in increasing lubricant thickness for metallic hip implants.

Introduction: COVID-19 is a disease caused by a new strain of coronavirus spreading rapidly over the globe, and the older population has had a larger impact as the fatality rate increases with age. This pandemic caused them to reduce their physical activity (PA). COVID-19 also resulted in food supply disruption and led to unhealthy dietary changes, which are usually associated with weight gain and affecting the body mass index (BMI). PA and BMI can influence the quality of life (QoL) of the older people. Therefore, this study aimed to determine the association between PA, BMI, and QoL amongst the older people in Malaysia during COVID-19. Methods: A cross-sectional study was conducted amongst community-dwelling older people from all states in Malaysia. An online survey consisting of self-reported anthropometry, Global Physical Activity Questionnaire- Malay version (GPAQ-M) and Short Form-36 Health (SF-36) Survey were collected. Statistical analysis chi-square test was used to identify the association between BMI, PA, and QoL. Results: This study included data from 180 individuals with a median age of 64.0 ± 9.8 years. The results showed that participants aged 60-69 years were significantly associated with better QoL, meanwhile, those who practice low PA levels were significantly associated with poor QoL. Conclusion: The findings revealed that age and PA were associated with QoL. Thus, the healthcare profession must emphasise regular PA to accomplish a better QoL amongst older people in the future.