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“Development of Realistic Computational Models of Osteoarthritis”

May 3, 2019

Dobbin Atlantic Scholarship Report:

Name:                                 Barry McDermott
Home Institution:        National University of Ireland Galway (NUIG)
Visited Institution:      Dalhousie University

Title of Research:
Development of Realistic Computational Models of Osteoarthritis

Visit Details – March/April 2019:
I was fortunate enough to be made a Dobbin Atlantic Scholar and given the opportunity to visit Canada for the first time in March of 2019.  I visited Halifax, Nova Scotia and was hosted by Dr Rebecca Moyer, principal investigator of the Laboratory for Clinical Biomechanics and Rehabilitation in the School of Physiotherapy at Dalhousie University.

Part of Dr Moyer’s research interests is the study of osteoarthritis (OA) of the knee. A facet of this research is the interpretation of magnetic resonance imaging (MRI) images from patients to identify patients at risk, those who may benefit from joint preserving surgery, and the tailoring of physical activity regimens designed to maximise benefit but minimise damage. The goal of the visit was to initiate the development of computer models of arthritis that could virtually study these research goals and would correlate with actual patients.

My home laboratory, the Translational Medical Device Lab at NUIG is a cross disciplinary group that combines medicine, science and engineering to help advance medical technology in a wide variety of areas. The primary area of research of my PhD is novel diagnostic imaging for stroke, but I myself am a cross disciplinary researcher being a qualified Pharmacist, Veterinarian and Electronic & Computer Engineer. As such the chance to work on another novel project that combined medical science with engineering was a perfect fit for me and one that I was excited to try!

The visit to Dalhousie also gave me the opportunity to initiate a unique collaboration between our two groups to develop innovative medical technologies, and to support a stronger understanding of orthopaedics for my future work at NUIG.

Research and Development Conducted:
The initial part of my time was spent studying and familiarising myself with the MRI data sets provided to me by Dalhousie. These data sets contained images of osteoarthritic knees with varying degrees of damage. With the research team at Dalhousie, we discussed what would be desirable in a set of computational models, the desired parameters that should be emulated, and the expected results generated by the computer. Although a trained veterinarian with knowledge of orthopaedics, there was a requirement on my part for some learning of aspects of OA outside of my primary area of animal disease.

The second phase of my work involved applying my engineering skillset and expertise in technologies, including computer aided design and mathematical modelling techniques, which could emulate joint structure, movement and tissue damage using computational models. These manipulations resulted in a collection of models that our team can use to better understand the internal structural response of joints to loads and interventions.

Experimental Procedures and Results:
I developed a procedure to segment out the knee joint anatomies of normal and osteoarthritic patients from MRI images. These patients ranged in the severity and nature of the disease. The segmentation process involved using computer to extract out tissues of interest from the MRI images which included the femur, the tibia, and the various cartilage layers (femoral cartilage, medial and lateral tibial cartilage, medical and lateral menisci). These segmented models had anatomically accurate 3D representations of the patient’s bone and cartilage tissues.

At the same time an “ideal knee” was developed using computer aided design (CAD). This knee could be modified to flex or extend the joint, damage the cartilage, introduce abnormal rotation into the joint and to perform corrective surgery.

(Left) Computational Model of the Knee Joint and (Right) The predicted result of damaging the cartilage

 

 

 

 

 

 

 

 

 

 

 

The anatomically accurate models of real patient data were then used to modify the ideal knee to be a CAD model of the patient’s joint. This CAD model was then divided into smaller parts which then can have simulated physical forces applied and the outcome calculated using the computer. This is known as the finite element method (FEM). The applied forces mimicked joint loading under different conditions with the stress and strain on the joint calculated and visualised. Using these techniques, the stress and strain on a damaged joint can be assessed under a particular loading and it can be seen if the stress and strain reduces if a different pattern of loading is used or indeed if surgery is performed.

A suite of FEM models was produced which varied in degree of flexion, cartilage damage, rotation and could have a range of simulated loads applied. The tools developed are extendable and flexible to allow modelling of a wide range of scenarios. The preliminary results generated correlated well to real world patients and make us think the approach and collaboration will be very successful!

Contacts Made:
This trip has opened a new set of academic links between NUIG and Dalhousie in the area of Biomedical Engineering. Dalhousie is the largest research focused academic institution in Atlantic Canada. Health research is a long-standing priority area driven by person-oriented and clinical research with translational research and health technology a major initiative. These values are an excellent match with my lab in NUIG which specialises in translational medical technologies. The time in Dalhousie has resulted in the forming of several relationships which will be built on as the collaboration continues including:

  • Dr Rebecca Moyer: Principal Investigator of the Laboratory for Clinical Biomechanics and Rehabilitation in the School of Physiotherapy. I worked mainly with Rebecca while at Dalhousie, and future collaboration will be with her group and her work on using MRI images to make effective interventions with osteoarthritis patients.
  • Prof Cheryl Kozey: Cheryl is also involved in bone and joint disorders (including knee OA). She is attached to both the Schools of Physiotherapy and Biomedical Engineering.

Future Continuing Collaboration/ Conclusion:
The work done over the 5-week period culminated in an initial set of models, with the ability to move the joint, emulate cartilage damage and perform virtual corrective surgery. The preliminary set of results indicated the models were matching what would be expected in real world patients. As such it was a successful and extremely encouraging research visit.

We have firm plans to continue the collaboration and marry our unique and complementary skill sets across the two laboratories, universities, and countries. We plan to refine and further extend the models, validate them with real patient data, apply machine learning techniques and ultimately be able to objectively use MRI images of arthritic knees to identify patients at risk, indicate patients who would benefit from surgery, and optimise physical activity for patients. The goal is to develop between the universities a technology that will aid in preserving and keeping affected knees as healthy as possible for as long as possible.

Other Notes:
My 5 weeks in Nova Scotia were memorable and a time I will forever cherish. It gave me the opportunity to visit a region I never thought I would have the chance to see, and a chance to truly get to know the city and its people. Over the course of my time there I had the opportunity to see some classic tourist attractions (for example the famous Peggy’s Cove) but also have some unique experiences with the people I was working and staying with. The latter included Easter dinner with Prof. Kozey and friends from Dalhousie, multiple trips to see the Halifax Mooseheads ice hockey team during their playoff adventure (they had reached the finals when I was leaving, and I am eager to see how they manage without my support!) and trips to the city theatres.

Peggy’s Cove, Nova Scotia

I was made to feel extremely welcome by the people of Halifax and would like to thank them sincerely for making my time there special. Working in an area of research that is different yet parallel to my own has helped widen my knowledge base and skill set. The Scholarship period in totality was an absolute success for me and I would like to sincerely thank the ICUF, Dalhousie, and the people of Nova Scotia I met and shared time, talk and many laughs with during my time in Halifax.