Our Research team operates out of our St Leonards 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. 

Akhmal Hakim

Hakim Ariffin, MEng

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.

Hugh Anderson, BEng

Clinical Research Administrator

Hugh has spent six months interning with SORI where he developed 3D prediction models to identify patients who are at high risk of developing isolated radial tears within their lateral menisci. The project is ongoing and being completed alongside an undergraduate degree in biomedical engineering at UTS and working at SORI as a clinical research administrator.

As a CRA, he is responsible for collecting and managing patient data to assist the research team in various projects as well as other administrative duties.


Sadia Siddiqui, BSc

Clinical Research Administrator

Sadia has completed a Bachelor degree in Science with a major in Biomedical Science from UTS. She is currently completing her Honours in Biomedical Science with her project focusing on developing a regenerative therapy for osteoarthritis while being part of the research team at SORI.

Her role as a clinical research administrator at SORI includes collecting patient data, data auditing, administrative duties and maintaining clinical data.

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.

Current Fellows

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Dr George Jacob

Clinical Fellow

Dr George Jacob completed his MBBS degree and MS Ortho degrees in South India, completing his residency in April 2017.

He then completed a Fellowship in Arthroplasty and Arthroscopy at Lakeshore Hospital, Cochin from June 2017 to June 2018. He then moved to Osaka, Japan where he was a Research fellow at Osaka University from Dec 2019 to Jan 2020 with Professor Norimasa Nakamura. While in Japan he focused his research on meniscal and cartilage regeneration techniques using MScs, Exosomes and Tissue Engineering.

George then returned to India and worked as Junior Consultant at SSIOT hospital, Mangalore, India.

He has now joined as a Clinical Fellow in Knee Surgery at the Sydney Orthopaedics Research Institute.


Dr Cristián Brito Ayet

Clinical Fellow

Cristián Brito Ayet obtained his MD degree from Universidad Andrés Bello in Viña del Mar, Chile. In 2014, he joined the Chilean Navy as a medical Officer. He completed his training as Orthopaedic Surgeon at the Universidad de Los Andes, in March 2022 in Santiago, Chile. During his residency, he developed a keen interest in knee surgery, from sport injuries to arthroplasty, that he seeks to expand gaining further exposure at SORI clinical fellowship.

Besides his academic interests, he likes football and golf. He came to Australia with his wife Pilar and his daughter Jacinta, who are both very excited and challenged of living overseas with a different language and way of life.


Dr Sarah Bolton

Clinical Fellow

Dr Sarah Bolton is an Orthopaedic Surgeon from the UK. Sarah graduated from Kings College London Medical School in 2011. She obtained a First class honors in Physiology, as part of an Intercalated BSc, during her Medical degree. She completed her Orthopaedic training on the Stanmore RNOH Rotation in London in April 2022. This is her first post CCT fellowship.

During the fellowship, Sarah is hoping to gain further knowledge and exposure to sports knee surgery, osteotomies around the knee and navigated/robotic knee arthroplasty.

Outside of work Sarah is a keen sportswoman, having played National League hockey for a number of years and now competes in Ironman triathlons. Due to her passion for exercise, Sarah understands the importance of sport, recovery and rehabilitation for patients.


Dr Payam Tarassoli

Clinical Fellow

Payam Tarassoli is an orthopaedic surgeon who undertook his training in Bristol, UK. Prior to starting his fellowship at SORI he completed a one year fellowship at Sydney Knee Specialists in robotic arthroplasty and soft tissue knee surgery.

Payam’s previous research includes robotic fracture surgery, concepts in knee alignment, and now with SORI is involved with imaging data following ACL injuries. He enjoys soccer, cycling and running.