Our Research team operates out of our Chatswood office, while also collecting data at the Mater and RPA hospitals. Working across the organisation, our researchers regularly collaborate with other community service agencies, universities, research institutes and government agencies to complete research studies.

Research Team

Samuel Grasso

Samuel Grasso B. Engineering, PhD

Clinical Applications Engineer

Samuel has completed a Bachelor of Mechanical Engineering degree and a Doctor of Philosophy in Biomedical Engineering (2018) at the University of Sydney. His research incorporates computational and image based methodologies to measure and optimise ligament position in ACL reconstruction on a patient specific basis, to improve pre-surgical planning processes and post-operative assessment.

Samuel is responsible for Sydney Orthopaedic Research Institutes research and development activities involving computational modelling.

Yoong Lim

Yoong Lim PhD

Research Associate

Yoong is a research associate and conducts biomechanical research relating to knee conditions. Here, he conducts biomechanical experiments and computational analyses using SORI’s state-of-the-art 3D biomechanics laboratory. Yoong’s current research projects are return-to-sport assessments for anterior cruciate ligament (ACL) reconstruction patients and gait analyses for ACL and high tibial osteotomy (HTO) patients. His research interests are musculoskeletal modelling and ultrasound image processing.

Yoong has completed postdoctoral trainings and a PhD (Biomechanical Engineering, University of Melbourne) on computational and experimental biomechanics.

Harbeer Ahedi

Harbeer Ahedi, PhD

Senior clinical research associate/ Database manager

Dr Harbeer Ahedi has a PhD in biomedical sciences with an extensive background in Osteoarthritis, data management and statistics. Her career has been a balance between academic and clinical research. As a researcher her focus has been on developing preventive techniques to reduce incidence of Osteoarthritis (OA) and improve the utilization of imaging modalities to study the epidemiology of OA. Currently she is the Senior Research Assistant/Data Coordinator at Sydney Orthopedic Research Institute. 

Shane Ball

Shane Ball, PhD

Clinical Research Associate

Shane is a clinical research associate and is responsible for data collection, data auditing and project support.

Shane has completed his PhD in health sciences at the University of Sydney, where his research investigated training and injury in rugby union. Having developed an interest in statistics through his PhD, he is now completing a post-graduate biostatistics degree.

Nadia Mazari

Nadia Mazari, BSc

Clinical Research Associate

Nadia has worked as a Clinical Research Associate at SORI since March 2016. She is currently studying a Master of Nutrition and Dietetics at the University of Sydney while working at SORI part-time. Nadia can be seen working across our research rooms with our surgeons in Newtown, Crows Nest and Chatswood.


Over the years, Nadia has been involved with numerous roles at SORI including the maintenance of our database of over 10 000 patients, developing standard operating procedures, and managing patient clinical data. Currently, her primary responsibilities involve clinical data collection, data auditing and supporting the SORI research team with ongoing projects.

Akhmal Hakim

Hakim Ariffin, BEng

Clinical Research Associate - Engineer

Hakim has completed a Bachelor degree (Vanderbilt University, USA) and a Master degree (University of Sydney). Both degrees are on Biomedical Engineering. He is an experienced biomedical engineer who has previously worked for both Canon Medical and St. Jude-Abbott.

At SORI, Hakim is working alongside the clinical research team in maintaining high quality clinical data collection and management. In addition, Hakim is working on computational modelling and analysis of orthopaedic patients data, and also assists in supporting IT resource.

Cathy Daniel

Cathy Daniel BSc (Ex Sc)

Clinical Research Associate

Cathy has a Bachelor Degree in Exercise Science from UNSW, and has many years of experience working in healthcare, both in the public & private sectors, as well as the corporate field. She enjoys interacting with patients on a daily basis.

Cathy’s role at SORI includes patient data collection, maintaining the high standards of the patient database, & assisting the Research team with ongoing projects.

Outside of SORI, Cathy enjoys time with her family, and loves trail-running on the beautiful bush trails around Sydney.


Finance and Administration

Lionel Jeyaraj

Lionel Jeyaraj FCCA, FIPA, FFA

Finance and Administration

Lionel is a member of the Chartered Association of Certified Accountants UK and Institute of Public Accountants in Australia. He brings over 30 years of extensive domestic and international business accounting and advisory services, including eight years in the accounting profession. He has accumulated a wealth of experience in business management, tax accounting and compliance, financial analyses, auditing, statutory and ASX reporting, technology and change management. Lionel is focused on business results and improvement though effective processes, systems, reporting and efficient asset management.

Lionel has industry experience in various capacities ranging from Accountant to CFO encompassing information technology, telecommunications, education, gaming, leisure, research, marketing, venture capital and not for profit organisation.


Jonathan Warnock

Dr Jonathan Warnock

Clinical Fellow

Jonathan Warnock is an Orthopaedic Surgeon from the UK.  He completed the FRCS (Edinburgh) in February 2020 before completing his training in Northern Ireland. Jonathan has previously completed an Arthroplasty Fellowship (Musgrave Park, Belfast, UK) and is keen to gain further exposure to all aspects of knee surgery in Sydney.

Previous research has revolved around Total Hip Arthroplasty and biomechanics and he is keen to pursue similar aspects in Knee Arthroplasty.  Jonathan is also keen to develop his knowledge and skills for managing sports knee injuries, at amateur and elite level.

Interests include rugby union, football and he is a keen golfer. He is also interested in return to sport after TKA- especially return to golf.

He has travelled here from the UK with his wife Catriona and young son Rory who are looking forward to experiencing a different way of life and better weather than they are used to.


Dr Ravi Teja Rudraraju

Clinical Fellow

Ravi Teja Rudraraju is an Orthopaedic Surgeon who has completed his residency training in
Hyderabad, India and has been practicing as a Hip and Knee specialist with a focus on sports
medicine and lower limb arthroplasty for over 5 years. He worked as a visiting fellow in sports
medicine and adult reconstruction at Cleveland Clinic, FL, USA for a year and later did his clinical
research fellowship in adult reconstruction at Geisinger Clinic, PA, USA. He has done an AOA clinical
fellowship in joint replacements in Melbourne and a revision arthroplasty fellowship in South Korea
before moving on to his present fellowship in Sydney Orthopaedic Research Institute. His research
interests are in Pre-operative Planning, Robotic and Computer Navigation Surgery and Periprosthetic
Joint Infections. He likes travelling, hiking, biking and swimming which he does on his weekends.

Johanna Elliott

Dr Johanna Elliott

Clinical Fellow

Johanna Elliott is an Australian AOA trained Orthopaedic Surgeon who completed her qualifications in Duesseldorf Germany and has been practicing as an Orthopaedic Specialist with a focus on lower limb arthroplasty and trauma for over 12 years. She holds a position on the Ethics Committee for Medical Research at Essen University. She has returned to beautiful Sydney, the city where she was born, to learn the latest technological advances in precision knee surgery. Johanna is in the process of completing her PhD at the University of London and maintains a consultancy position at the EPRD in Berlin (German Arthroplasty Registry). Her general research interest are the public health implications and outcomes of lower limb arthroplasty, with a focus on scientific documentation of advancements in these medical products.