Canterbury researcher producing hip replacement sound device

Canterbury researcher producing hip replacement sound device

July 8, 2014

A University of Canterbury mechanical engineering researcher is working on a sound device to listen to the performance of hip and joint replacements.

Dr Geoff Rodgers is helping Christchurch Hospital’s orthopaedic department to develop a device which monitors patients with hip replacement implants. The device is intended to help surgeons diagnose any implant problems and manage patient treatment and revision surgery.

“The monitoring technique measures vibrations that are created by the implant and make it through tissue to the skin surface,” Dr Rodgers says.

“The vibrations are related to observed implant failures and clinical outcomes to help detect implant loosening or any deterioration. The monitoring technique could also be used to assess the performance of different implant designs.

“The ability to observe sounds and relate them to implant condition is entirely non-invasive and can detect issues when a patient is moving. This is just not possible with traditional techniques such as x-ray, where patients are required to remain still.

“Results to date have shown some significant promise, with the movement between different implant components displaying clearly different sound signals. We can also detect loosening of the implant within the bone and sounds such as squeaking, grinding or clicking from the implant.”

Total joint replacement surgery is typically the last resort for people with osteoarthritis also known as degenerative joint disease. Joint replacements are on the rise, largely due to demographic ageing.

The number of total knee replacements performed in the United States will leap by 673 percent to 3.48 million by the year 2030 with hip replacements increasing 174 percent to 572,000.

Replacement surgery is extremely successful but joints need to be replaced due to wear or premature loosening of the implant after every 10 to 15 years.

“The more primary joint replacements surgeries there are, the more revision joint replacement surgeries there will be, creating a significant and increasing burden, in dollars and use of limited surgical services.

“This epidemic of total joint replacements creates a huge challenge to develop and implement effective screening programmes for detecting early wear or failure, and clear diagnostic indicators for orthopaedic surgeons to properly manage revision surgery.

“Long-term, patients could wear the device over hours or days during their normal day-to-day activities, allowing surgeons to assess patients under conditions not previously possible.”

Dr Geoff Rodgers is collaborating with Dr Tim Woodfield and Prof Gary Hooper at the University of Otago.

ENDS

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