Dodgy hips? Get Robodoc to f ix them!

BRITISH surgeons are performing hip replacements with the help of a revolutionary robot ‘assistant’, a l l o wi n g p i n p o i n t accuracy that means the implants could now last for ever.

Artificial hip joints typically last between ten and 20 years and can wear out during a patient’s lifetime, depending on when people first have the procedure and how active they are. One reason implants fail is because they are misaligned with the patient’s anatomy. Components can rub against each other and, over time, wear away.

But the Mako robot – a motorised arm that guides the surgeon’s hand – can vastly improve accuracy. It compares whether the surgeon’s hand movements are in line with a 3D image of the patient’s hip created from a CT scan before surgery.

The image allows a computer to work out the best angle in which to place the hip ball and socket so that it matches the original location as closely as possible.

During surgery, the robot arm and doctor both hold the instruments. If the surgeon is not aiming for exactly the right area, the robot nudges the surgeon’s hand into the correct position. ‘There is a limit to what the human eye and hands can do in getting an implant aligned as closely as possible to the patient’s natural hip,’ explains consultant orthopaedic surgeon Professor Robert Middleton, who has been carrying out the procedure at the Nuffield Bournemouth Hospital since last autumn.

‘We can usually achieve within five to ten millimetres accuracy by hand but with the robot one to two millimetres is possible.

‘I’m still doing the operation but the robot arm guides my hand to make everything as precise as possible. If I am out by more than two millimetres, it not only nudges me, but red lights show up on the computer monitor as an alert.’

Prof Middleton hopes the new procedure will bring a wealth of benefits for patients and is now conducting a trial at Bournemouth University into its long-term effects. ‘It seems logical that if you can get a perfect fit, the longevity of the implant will improve,’ he says.

Two recent studies have confirmed the accuracy of the robot.

At present, the device is available only at private centres in Bournemouth, Exeter, Edinburgh and London. Surgery costs about £12,000, including rehab.

Peter Flinders, 75, from Bournemouth, has had two hip replacements – the second was guided by the robot. He says: ‘After the first op I had some post-surgical pain. I was on crutches and sticks for more than six weeks. But with the robot operation I had hardly any pain, was off crutches in under three weeks, and was going for long walks in about five weeks.’