New 3D model to help osteoarthritis patients

Published: 8 April 2014 at 11:20

Anglia Ruskin scientists develop tool for surgeons to reduce knee replacement operations

Scientists at Anglia Ruskin University are the first in the world to develop a 3D model to predict knee stress, based on validated force and movement data, which can help osteoarthritis patients delay the need for full knee replacement surgery and potentially save the NHS millions of pounds every year.

Working alongside colleagues at the Hospital for Special Surgery in New York, experts at Anglia Ruskin’s Medical Engineering Research Group have built a model to predict pressure in the knee joint following less intrusive surgical reconstruction procedures.

Osteoarthritis is a debilitating disease that often leads to pain and disability in the elderly.  About 14% of men and 23% of women over 45 years of age show signs of knee osteoarthritis and the NHS performs over 70,000 knee replacements every year in England and Wales.

Dr Rajshree Mootanah, Director of Anglia Ruskin’s Medical Engineering Research Group, said:

“There is no cure for osteoarthritis and joint replacement is often the ultimate solution.
“Total knee replacement is expensive, involves the removal of ligaments and alters the knee function.  Therefore, it is important to treat knee osteoarthritis as early as possible and preserve the natural joint tissues.  This model can help surgeons with that procedure.”

To create the computerised model, high-resolution magnetic resonance images of a 50-year-old cadaveric knee were obtained at the Hospital for Special Surgery in New York.  The relevant tissues were segmented by scientists at Anglia Ruskin to create an accurate 3D representation of the knee joint.

Material properties of the different tissues were then allocated to the bones, cartilage, meniscus and ligaments.  The cadaveric knee was fixed on a six-degree-of-freedom robot, controlled loading was applied and knee joint pressures were measured.  

Following a special technique, called the ligament tuning process, the material properties of each ligament were obtained at every position of the knee joint.  The same loading conditions, applied on the cadaveric knee, were simulated in the knee model and joint pressures were predicted.  

The experimentally-measured and computer-simulated knee pressures were compared to validate the knee model, which is now being used at Anglia Ruskin and the Hospital for Specialist Surgery to evaluate surgical techniques, such as knee realignment and partial removal of the meniscus, and help patients delay the need for full knee replacement surgery.

The work was sponsored by the Chelmsford Medical Education and Research Trust.

Details of the research are due to be published in the latest edition of the Computer Methods in Biomechanics and Biomedical Engineering journal, available on Thursday, 10 April.