Papers by Author: Chia Chi Lo

Abstract: An important breakthrough of orthopedic surgery is to use bone cement to fill the space between an artificial joint and bone tissue, which allows the artificial joint to stabilize on human bone tissues. However, surgery failure cases due to bone cement utilization and side effects still exist at present. Therefore, the purpose of this study is to investigate bone cement characteristics, such as coagulation time, consolidation time, maximal exothermic temperature and anti-compressive strength, etc. under different mixture ratios. Our results showed that the smaller the ratio of polymethyl methacrylate and methyl methacrylate (PMMA/MMA), the lower exothermic temperature and the stronger anti-compressive resistance. These results are helpful to reduce incidences of post surgery side effects. Of note, bone cement supplement decreases corresponding to loading and operating time, which will become a major challenge for orthopedic surgery.

Abstract: Nowadays, electroencephalogram (EEG) is widely used in medical applications. Besides the examination for brain diseases, EEG is used to observe how the surroundings affect peoples emotion. There are many essential oils, and most claim that they are effective in soothing soul and calming. Currently, there is no related EEG scientific experiment to verify this claim, This study attempted to understand whether common essential oils for stress relief have actual emotional relaxation effects on the human brain by EEG observation; the level of efficacy was also observed. From the results of this study, rose essential oil had the best effect of stress relief and relaxation in both genders (P<0.05). It suggested that peppermint essential oil had the best effect of relaxation in male (P<0.05) and rose essential oil had the best effect of relaxation in females (P<0.05) when it was analyzed by gender.

Abstract: Despite the fact that total knee arthroplasty has become the major treatment for degenerative arthritis, damage to the patellar components remains an unsolved problem as the weight and the postures of a patient keep bringing about stresses on specific points, lines and planes between the patellar and the femoral components and thus lead to the wear and breakage of the former or even an additional knee arthroplasty surgery in a critical situation. To fulfill the need to have an in-depth examination on the contact behavior of the patellofemoral components, the current study conducted in vitro simulation on patellofemoral components with varied designs to mimic different real-life knee flexion angles and to explore the contact behavior in the patellofemoral components. The results of the study showed a higher stability in onlay patellar component when compared to inset patellar component at different knee flexion angles.

Abstract: Complications in total knee arthroplasty (TKA), which may include the inaccuracy of the implantation and the poor component design, can cause major failures in the TKA. Therefore, the present investigation studies the onlay knee implants commonly used clinically to find the major causes of the damage to artificial patella by the computer aided analysis of the three-dimensional finite element model of the artificial patello-femoral joint built through reverse engineering. Results showed that although a significant difference is found in the condition and the state of the stress distribution generated as the patello-femoral joint changes with the flexion of the knees, this variation is still within the tolerable range; but the patellar lateral tilt is something that caught our attention. Furthermore, through the comparison between the study and the clinical results, this investigation concludes that the bone cement on the implant interface is the major cause for the breaking of the pegs, and is not related to the original design of the patella. This study also discovers that slight design modification on the parts of commonly used artificial joints may effectively reduce surgical failure rate; therefore, a more robust design configuration for patellar pegs is proposed.

Abstract: The development of artificial joints is now considered quite mature, and the main treatment for osteoarthritis. However, in recent unicompartmental knee arthroplasty (UKA) clinical follow-ups, complications due to wear of polyethylene (PE) tibial components still exist. Therefore, this study focused on the possibility of avoiding and minimizing damage to the PE tibial component. Currently, the most common problem in the application of UKA is the malresection of the tibial plateau, often resulting in malpositioning of the tibial implant. This positioning problem may be the main reason for advanced wear and dislocation of a PE tibial component. In this study, finite element analysis (FEA) was used to study the stress change of malpositioned PE tibial components in order to better understand the damaging mechanism on PE tibial components. It was found that anatomically designed unicompartmental knee prostheses (UKP) allowed more positioning error in varus tilt than symmetrically designed ones. And both should avoid any positional error greater than 10° valgus tilt. Otherwise, increased wear of PE tibial components would result in shortened lifetime of the artificial joint.