It’s painful, inconvenient and costly. But if detected early, implant loosening – the slight movement of a newly replaced hip – can be dealt with, without the need for a major follow-up surgery, according to a group of Western students.
Roughly half a million patients undergo a hip replacement surgery each year in North America. Of those patients, about 5 per cent – or 25,000 – will experience implant loosening and require a follow-up hip surgery because of resultant bone weakening.
“The implant becomes loose, and sometimes, there’s not always symptoms associated with this. It’s called ‘aseptic loosening,’ which happens without an infection so you don’t know (it’s moved) until it’s too late, until it starts wearing down the bone,” said Jolien Van Gaalen, an Engineering student studying mechatronic systems.
“The patient goes in, and maybe is experiencing pain at this point. The patient would have to get a scan that is not widely available and at that point you can already have permanent damage to the bone,” she continued.
Currently, there are only four places in Canada equipped to do the type of scan that could detect implant loosening – a shift that occurs on a scale of micrometers. The scan isn’t just widely unavailable – it’s also incredibly costly.
But Van Gaalen, along with three other Engineering students, has helped design a potential solution, engineering a smart implant that could detect loosening early on. The smart implant can wirelessly transfer data to a medical centre, requiring a visit to a local doctor and only a minimally invasive procedure to fix the problem.
Van Gaalen worked on the project with Hilary Luo, Mofeed Sawan and Peter Nielsen, while Robarts Research Institute researcher David Holdsworth supervised.
Their implant design took top prize in the Western Engineering Competition earlier this year and the group placed third in a provincial conference.
“This method can detect early on when there is loosening, so patients can do a minor revisional surgery. The patient doesn’t need to have to leave their home because the data can be transferred to a cloud and the doctor can look at that,” Van Gaalen said.
“We wanted to do something with sensorized implants because that’s something that’s big, and coming up in the future. We had a lot of 3D-printing technology we could use to our advantage at Robarts,” Nielsen said.
“We were thinking maybe we could try and make (detecting the implant loosening) cheaper with something more along the lines of embedded technology. We were talking with orthopedic researchers and we realized nobody had been able to properly create a mechanism of detecting micro loosening,” Sawan added.
“We thought there was a huge amount of potential. People said it was impossible – everyone told us we were wasting our time, and we were, until we came up with a solution nobody had thought of before.”
Sawan and Nielsen noted their idea is pending a patent and, therefore, cannot discuss the particulars of how the smart hip implant works, although they did say it involves vibration sensors.
“The real challenge with it is the loosening of an implant is on a scale of micrometers – less than a 20th of a millimeter. We’ve currently tested at 10 times that scale. We’re still working on refining that system, but right now, what we’ve shown is that our system has the potential to work with those small loosenings,” Nielsen explained.
“It’s not something we can put into a person tomorrow, but it has shown promising potential to succeed.”
