Reported by Helen McArdle – Herald Scotland
SCOTS researchers have revealed plans to create a revolutionary new hip implant that will use the latest stem cell technology to allow patients to grow their own bone, removing the need for regular replacement surgery.
The prosthetic implants are being developed by scientists at Glasgow University in collaboration with orthopaedic surgeons at the city’s Southern General Hospital and they hope to have a prototype ready within 10 years.
The move follows a breakthrough last year by a team at the university’s Institute of Molecular, Cell and Systems Biology when they succeeded in creating a special plastic surface capable of controlling what stem cells become – a technique that was previously impossible.
The plastic is covered in tiny pits 120 nanometres across which, when stem cells are placed on the surface, encourages them to grow and spread across the pits in a way which ensures they differentiate into therapeutically useful cells.
While the implant itself will be made of an advanced polymer, already commonly used in spinal and other orthopaedic procedures, it will be coated for the first time in the university’s unique plastic. As a result, once inserted into a patient’s bone marrow – a rich source of mesenchymal stem cells – these can be made to divide and differentiate into fresh bone cells, creating a much stronger and more durable implant.
Dr Matthew Dalby, a specialist in bone tissue engineering at the institute, said: “By covering the implant in this surface, we can ensure the mesenchymal stem cells differentiate into the bone cells.
“This will help the implant site repair itself much more effectively than has ever been possible before and could well mean implants will last for the rest of patient’s life.
“People are living longer – long enough, in fact, that we’re outliving the usefulness of some of our body parts. Our new implant could be the solution to the expensive and painful follow-up surgeries which conventional implants require.”
Currently, implants are commonly made from materials such as polyethylene, stainless steel, titanium or ceramic and tend to require replacement every 15 to 20 years.
In hip replacement surgery, the head of the thigh bone is removed and replaced with an implant which is held in place by a rod fixed inside the marrow along the length of the bone.
When traditional implants are fixed into bone marrow, the marrow’s stem cells do not receive messages from the body to differentiate into bone cells.
Instead they usually differentiate into a build-up of soft tissue which, combined with the natural loss of bone density that occurs as people age, can weaken the bond between the implant and the body.
Safety concerns over metal hip implants were also raised earlier this year when it emerged thousands of Scots patients could be at risk from a build-up of toxic debris from DePuy ASR implants, which were first used on the NHS in 2003.
