In an Australian first, humans are now replacing robots in orthopaedic surgery.
Content warning: This article contains an image of surgery
An orthopaedic surgeon has performed the first 3D-printed, custom knee replacement surgery in regional Victoria.
The US-made technology became available in Australia in March and has been used by fewer than 20 surgeons, mostly in metropolitan areas.
Traditional knee replacement implants are offered in a variety of generic sizes but are not always a perfect fit, forcing surgeons to cut further into bones to complement the implant.
Conversely, custom implants are printed to match the patient's knee anatomy exactly, potentially reducing the amount of bone that needs to be removed.
A 3D CT scan is performed to map the anatomy of the patient's knee joint and is then sent to orthopaedic biomedical engineers in the United States who produce a virtual 3D model of the knee.
A knee replacement surgery is then simulated to calculate the appropriate size and fit of the implant which is then printed using a 3D printer.
The implant, along with single-use, patient-specific instruments is then sterilised and couriered to Australia.
Simplifies surgery
Orthopaedic surgeon Ilan Freedman performed the knee replacement surgery at Maryvale Hospital in Morwell and said the technology simplified the operation.
"We do know that not everybody's bone is the same, people might be between size three and size four," Mr Freedman said.
"Some [people] have more curved femurs or different shapes of the bone."
Mr Freedman operated on Lorraine Watson who said the idea of a custom implant and convenient location appealed to her.
"You just haven't got the hassle of getting to Melbourne and you're not so far away from home and we've got family in the valley so it's a big bonus to us," Ms Watson said.
A US study comparing patients who underwent two knee replacements, one with a patient-specific implant and the other with a generic implant, reported better outcomes for their custom-made knee.
But although custom-made implants could be beneficial for some patients, Mr Freedman said traditional knee replacements could be equally successful.
"A pair of shoes that fits well is a pair of shoes that fits well, you're not necessarily going to do better every time," he said.
"What we are hoping is that by avoiding mismatching sizes, by ensuring that it's a custom fit then maybe we can avoid some of the problems with knee replacements."
Common operation
Data from the Australian Orthopaedic Association's National Joint Replacement Registry reveals that more than 62,500 knee replacements were reported in 2020.
The association estimates that about one in five knee replacement patients are unsatisfied with their outcomes.
"With traditional knee replacements about 20 per cent of patients are not happy, they have pain, they have delayed recovery and it doesn't feel quite right," Mr Freedman said.
Shortening rehabilitation
Maryvale Hospital's director of clinical services Daniel Scholtes said the implants should shorten rehabilitation and improve access to the surgery in regional areas.
"You don't require that capital requirement or the robots on site and so smaller facilities that may not do a lot of knee surgery will be able to provide this without having that equipment on hand," he said.
Robots have been used in Australia, more commonly, in the past five years to help guide orthopaedic surgeons to accurately cut bone and position implants.
Using a robotic system reduces surgical error but costs the hospital up to $1.5 million and increases surgical time.
Revisions because of infections following a robotic-assisted knee replacement is 12 per cent higher than for those who underwent surgery that was not robotically assisted, according to the Australian Orthopaedic Association National Joint Registry.
Cheaper option
It's understood that already-sterilised custom-made implants would eliminate the need for robotic-assisted knee replacements and lower costs for patients and hospitals through reducing the cost of sterilisation, saving $300 to $700 per knee replacement.
3D printers are also being used to create custom implants for patients needing major bone resection from cancer.
But Australian Orthopaedics Association general director Christopher Vertullo said not enough research has been conducted on the long-term success of the implants.
"We don’t really know how good they are or if they’re the same as what we have, better or worse," he said.
"You have to separate the marketing from the product, and at the moment there’s just no data."
