Issue 15, July 2008

Home | English | | | UGC | RGC
Research Endowment Fund Adds Momentum to Research
Potential Breakthrough in Coronary Bypass Surgery
Lighting Up Cancer Cells
Finger Joint Brings Hope for Arthritic Sufferers
Innovations Result in Industry Accolades
Clean Energy Alternatives Uncovered at HKUST
CityU Initiatives Lead to Major Energy Savings
Summary Brief for Collaborative Research Fund 2007/2008 Funded Projects

For Professor S P Chow, Chair of Orthopaedics and Traumatology at The University of Hong Kong, optimising the design and development of artificial finger joints is almost a personal project and it spans more than 30 years.

He first became interested in the potential of a prosthetic device for fingers during the 1970s while studying under the then master of hand surgery, Professor Alfred Swanson, in Michigan.

While artificial joint prostheses were successfully used in hip and knee joint replacements, no-one was achieving the same level of results with finger joint replacements.

The difficulty came in trying to reproduce the complex anatomical structure of finger joints. "The small size of the joint components presented long term clinical problems and made surgical procedures difficult," says Professor Chow.

Rheumatoid arthritis, osteoarthritis and post traumatic arthritis are the key causes of finger deformity, resulting in pain, joint instability and deformity, and a loss of hand function.

Professor Chow came up with a design for one-piece and two piece finger joint implants that ensured a locking ability required along the length of a finger while retaining shape, size and flexibility. The Industrial Support Centre, in HKU's Faculty of Engineering, identified suitable materials and manufacturing processes to produce the two joints artificially.

A prototype bronze model was prepared and, once this was judged workable, engineering and biological tests began.

The new prosthetic device is capable of providing pain relief, increased movement range, enhanced fixation and intrinsic joint stability. Professor Chow says it is also a very durable device.

Using RGC and HKU grants, the new device was subjected to a range of studies that focused on appropriate materials, biomechanical tests and animal experiments.

"Tests in chickens and animals have shown the prosthetic has good bone-implant fixation - existing bone will grow around it – and that as a joint it operates with flexibility and stability.

"It's not perfect, but our research group is constantly reviewing and refining the prosthetic and, at this stage, it is certainly better than anything I have seen to date."

The Research Grants Council and the Hong Kong University have helped finance studies to date and applications for further grants are under consideration. Meanwhile, Professor Chow and his team have been awarded the first of two patents for their development and are about to begin clinical trials with two patients.

Insurance costs associated with these trials however threaten the ongoing development of the prosthetic.

Clinical trials normally require 20 or 30 patients to be monitored for 20 years. The resultant insurance costs for the finger prosthetic over a 20 year period could amount to HK$12 million.

"Insurance issues are becoming common place in clinical trials and we face the real prospect that innovation and the development of new medical discoveries will be stifled because we simply cannot afford the insurance premiums. This is an area where Governments and the pharmaceutical industry need to come together, perhaps in a Greater China context, and look at just how academics and scientists can continue to discover, innovate and develop without being intimidated by unaffordable insurance costs for medical trials," Professor Chow said.

Professor S P Chow

Department of Orthopaedics and Traumatology
The University of Hong Kong