New arthritis implant really meets a (k)need

Anew implant is currently being developed that could revolutionise the treatment of knee osteoarthritis. team of researchers from AUT’s Engineering Research Institute and the University of Auckland are developing an implant that will act as a load distributor and aim to slow down and prevent the progression of osteoarthritis.

Osteoarthritis affects one in ten New Zealanders, with fifty per cent having at least one affected joint by 60.

In a healthy knee, a thin layer of cartilage covers the ends of the femur (thighbone) and the tibia (shinbone). The cartilage acts as a cushion, allowing the ends of the bone to easily glide over one another.

But with osteoarthritis, the cartilage starts to deteriorate, allowing the bones to rub together and become roughened, which causes pain and stiffness.

Mechanical engineering doctoral student Mehdi Saiedi said the implant, the first of its kind in Australasia, is made from cobalt chromium or titanium and ultra-high molecular weight polyethene that attaches to the internal side of the knee joint, allowing arthritic lesions to repair.

Saiedi is working on the implant’s flexibility, ensuring it feels natural.

Medication, physical therapy, weight loss and exercise ‘‘manage the symptoms, but don’t prevent the progression of the disease,’’ he said. There is no cure, and the most severe cases require total knee replacements.

The New Zealand Medical Journal published projections suggesting the demand for total knee replacements will increase 673 per cent by 2030.

People over 45, athletes and people who have suffered trauma to the joint are all more likely to develop osteoarthritis.

For younger people, osteoarthritis can mean ‘‘decades of chronic pain’’ before surgery, Saiedi said.

Even then, one in four people who have received a knee replacement are dissatisfied with the outcome, he said.

The implant would offer an alternative, slowing the progression of the disease and ultimately putting off the need for surgery.

Manager of health advice and research for Arthritis New Zealand, Cathie Morton, said each case was different: if someone starts exhibiting symptoms in their 30s or 40s, there is likely a higher chance that the severity will increase over time.

Morton said the most beneficial thing for osteoarthritis is movement, so an implant which would increase mobility and decrease pain associated with movement had ‘‘real promise’’.

While still in the development phase, the implant has been tested on cadavers, and the team hope to carry out trials on sheep soon.