Computational Biomechanical Modeling of the Human Knee During Kneeling

Total knee replacement benefits patients who suffer from severe knee pain or joint stiffness and other joint related illnesses that limit everyday activities. There has been an increase in the number of procedures performed each year and a need to evaluate the performance of these implants during specialized activities such as kneeling. Most computational studies lack insight into inter-patient variability and the results do not apply to large population. This study developed: (1) three-dimensional explicit finite element (FE) models to investigate natural and implanted knee joint kinematics and bone strain and (2) a platform to enable population-based evaluation by combining statistical model and joint function. Verification of a finite element model confirmed a strong agreement between model predicted and in-vitro kinematics of specimen-specific patellofemoral (PF) joints of four cadaveric knees in simulated kneeling. Three different commonly used PF implants were employed in an additional broader patellar bone strain study to assess the relative performance of these implants during highly demanding activities. This study predicted that the medialized dome design achieves the optimal balance of sufficient congruency between PF articular surfaces while still facilitating sagittal plane tilt to reduce isolated loading of the distal nose of the patella. A combined statistical shape model and FE method were utilized to successfully identify the most important shape characteristics affecting joint performance during kneeling. Scaling in the knee joint has minimal effect on PF joint kinematics but greatly affects joint contact mechanics. Knee soft tissue dimensions alter the kinematics. The patellar bone strain model described here provides a novel platform for further implant performance analyses. The statistical shape-function model is a tool for population based studies to help predict the clinical outcome of joint replacement

Effects of quality circle participation on employee perception and attitude in five Malaysian companies

This study investigates changes in employee attitude brought about through participation in Quality Circle (QC). Assessment of circle performance was measured by technical aspects, length of participation, training, member feelings about QCs, job satisfaction and job commitment. Study illustrates the impacts of participation on 130 workers from 5 Malaysian companies participated in a survey. Results show that QCs develop positive attitudes among employees who derive job satisfaction when they feel that their companies are a good place to work and consequently, more willing to extend their efforts for their companies

Effects of quality circle participation on employee perception and attitude in five Malaysian companies

This study investigates changes in employee attitude brought about through participation in Quality Circle (QC). Assessment of circle performance was measured by technical aspects, length of participation, training, member feelings about QCs, job satisfaction and job commitment. Study illustrates the impacts of participation on 130 workers from 5 Malaysian companies participated in a survey. Results show that QCs develop positive attitudes among employees who derive job satisfaction when they feel that their companies are a good place to work and consequently, more willing to extend their efforts for their companies

Patellar mechanics during simulated kneeling in the natural and implanted knee

AbstractKneeling is required during daily living for many patients after total knee replacement (TKR), yet many patients have reported that they cannot kneel due to pain, or avoid kneeling due to discomfort, which critically impacts quality of life and perceived success of the TKR procedure. The objective of this study was to evaluate the effect of component design on patellofemoral (PF) mechanics during a kneeling activity. A computational model to predict natural and implanted PF kinematics and bone strains after kneeling was developed and kinematics were validated with experimental cadaveric studies. PF joint kinematics and patellar bone strains were compared for implants with dome, medialized dome, and anatomic components. Due to the less conforming nature of the designs, change in sagittal plane tilt as a result of kneeling at 90° knee flexion was approximately twice as large for the medialized-dome and dome implants as the natural case or anatomic implant, which may result in additional stretching of the quadriceps. All implanted cases resulted in substantial increases in bone strains compared with the natural knee, but increased strains in different regions. The anatomic patella demonstrated increased strains inferiorly, while the dome and medialized dome showed increases centrally. An understanding of the effect of implant design on patellar mechanics during kneeling may ultimately provide guidance to component designs that reduces the likelihood of knee pain and patellar fracture during kneeling

Employees Perception on Quality Circle Program Effectiveness in Five Selected Malaysian Companies

The purpose of this study is to examine the effectiveness of participation in Quality Circles (QCs). The study looked at major factors affecting QCs effectiveness, which are namely; employees involvement, adequacy of training, leadership, employee perception, purpose of setting up QCs, number of projects implemented, management support, job satisfaction, commitment and willingness to expand effort, and intent to quit. An important aspect of this study was the fact that it took place in large manufacturing and service organizations where research on organizational commitment is rare and where commitment and QCs members’ feelings about their organizations are particularly troublesome. Therefore, out of seventeen companies, only five participated in this study. Subjects consisted of 130 employees from five manufacturing and service organizations who volunteered to participate in the study. 89-item questionnaire was developed to meet study objectives. While, QCs members (N=109) answered the whole questionnaire, non-QCs members (N=21) were directed to fill out the last part of the questionnaire. From the data obtained, Pearson Correlation test showed there was no relationship found between training and involvement in QCs, a very weak correlation between leadership and adequacy of training. Nonetheless, there was significant positive relationship between management support and scores of projects implemented. A one-way analysis of variance (ANOVA) test was performed to investigate whether or not scores of two groups namely QCs and non-QCs differ significantly. Besides improved problem solving skills that the results show, QCs develop positive attitudes among employees who derive job satisfaction when they feel that their companies are a good place to work. Also, they are more willing to extend their efforts for their companies. Even though, these impacts were more obviously seen in manufacturing QCs (N=56) than service counterparts (N=53), still the conclusion shows that the Quality Circles concept is still alive and effective