The following works were performed during the Fellowship:
(1) A patient-specific musculoskeletal multibody dynamics (MBD) model was developed using the AnyBody modelling system. The hip contact forces during seven daily activities (i.e. normal walking, ascending stairs, descending stairs, lunge, squat, standing up and sitting down) were predicted;
(2) A patient-specific FE model of the natural hip joint, which integrated the solid mechanics of the cartilage and the behaviour of the fluid flow within the joint, was developed using the FEBio software system;
(3) A multiscale computational modelling to couple the MBD model of the human body and the FE model of the natural hip joint was developed through a python script. The modelling was then applied to seven daily activities to investigate the biomechanics and tribology of the articular cartilage, in terms of the contact stresses, fluid pressures, stresses and strain within the cartilage over 80 cycles for each activity.
(4) A series of training, research and outreach activities have been carried out to disseminate and exploit the research outcome and improve the fellow’s capacity.
The main results:
(1) An innovative and advanced multiscale computational modelling pipeline to couple a MBD model of the human body and a FE model of the natural hip joint was developed in the project.
(2) The patterns of peak contact stresses and peak fluid pressures within the cartilage follow the patterns of the hip contact forces during a cycle of each activity, with higher peak contact stresses and peak fluid pressures predicting during ascending and descending stairs, and lower contact stresses and fluid pressures predicting during standing up and sitting down activities;
(3) For all the activities considered, when the contact areas approach to the rim of the cartilage layers, contact stresses and fluid pressures decreases over a long period due to the fluid flow out from the cartilage, leading to decreased fluid support;
(4) On the contrary, when the contact areas occurs at the center of the articular cartilage, the contact stresses and fluid pressures increase over a long period due to the creep of the fluid and solid matrix, and potentially “ploughing” effects.
Exploitation:
The developed multiscale computational modelling, when applied to the images of patients, can be used for treatment planning and joint disease prevention, diagnosis, and prognosis, which will address the rapidly growing demand for computer-aided medicine and personalised treatment within the healthcare sector.
The approach can also be used as an effective tool for pre-clinical testing and assessment, designing and optimising prosthetic products and new biomaterials.
Dissemination:
(1) The results of the project were submitted and presented in two international conferences, and will published in two peer-review journal papers.
(2) The developed multiscale computational modelling was presented in a summer workshop (Image-based Biomedical Modelling) at University of Utah in the USA in 2017, and in the 6th MCAA General Assembly and Annual Conference in Austria in 2019;
(3) The developed multiscale computational modelling and results were presented at University of Sheffield and Middlesex University in the UK, at Southwest Jiaotong University in China and at DePuy Company in the UK between 2017 to 2019;
(4) The FE technology for modelling the articular cartilage was demonstrated to the Master students in a master module.
