Study into Robotics in Joint Replacement Surgery

Mako robotic-arm assisted joint replacements have been around for the last 17 years. To date, more than a million Mako procedures have been carried out around the world and there have been 330 published, peer-reviewed studies.

Impressive data

Mako SmartRobotics technology has been hailed as a major breakthrough in joint replacement surgery and the data is certainly impressive. Patients who’ve had Mako surgery report higher satisfaction levels and lower pain scores compared with conventional joint replacements. Overall comfort and performance is also better due to more accurate alignment of the prosthetic implant.

RACER – new randomised controlled trial

A research team from the University of Warwick and University Hospitals Coventry & Warwickshire NHS Trust recently published an article in The Bone & Joint Journal highlighting the importance of more robust studies into Mako total hip replacements and total knee replacements.

The team has created the RACER study (The Robotic Arthroplasty Clinical and Cost-Effectiveness Randomised Controlled Trials) to assess Mako technologies and to explore the design and challenges associated with such trials. In particular, the researchers are interested in considering surgical workflows, isolating the effect of the operation, blinding and assessing the learning curve

These multi-centre, patient-blinded randomised controlled trials will focus on patients with primary osteoarthritis of the hip or knee who undergo a total hip or knee replacement using Mako SmartRobotics. The control groups will have conventional hip or knee replacement surgery.

Forgotten Joint Score

The researchers are using the Forgotten Joint Score as the primary clinical outcome 12 months after surgery. This is a 12-question patient-reported outcome measure that was created to measure the patient’s awareness of their artificial joint.

Among the questions it puts to patients are:

Are you aware of your joint
In bed at night
When sitting on a chair for more than an hour
When walking for more than 15 minutes
When taking a bath or shower?

Patients can answer: Never, Almost never, Seldom, Sometimes, Mostly or Not Applicable.

The researchers will also include a built-in analysis of cost-effectiveness and, as a secondary outcome, the RACER trials will look at early pain, the alignment of components and medium to long-term outcomes.

Currently recruiting

The RACER trials are currently recruiting and will include patients with primary osteoarthritis of the hip or knee. They are randomised to those who are having a total hip or a total knee replacement, either using Mako or conventional joint replacement surgery.

Isolating the effect of the robotic arm

All patients participating in the trial have a pre-operative CT scan which is used to create a pre-operative plan that sets out the size and positioning of the implant. The trial has been designed to isolate the effect, if any, of the robotic arm itself rather than the effect of this detailed planning. The team is keen to ensure that the only difference between the groups is the use of the robot itself. Randomisation is undertaken no more than three hours preoperatively to minimise systematic biases developing within operating theatre lists.

Post-surgical follow-up

Patients in the RACER trials will be contacted at two, five and 10 years post-surgery to collect patient-reported outcome measures and information about any joint revision surgery or follow-up procedures.

Evaluating new technologies

The research team believes this study has an important role to play in determining the future of robotic arm-assisted joint replacement surgery. They comment:

“Although new technologies may offer improved precision and associated outcomes, they are often associated with higher costs, while their immediate, medium or long-term benefits are often not evaluated alongside their introduction.”

They add:

“These blinded, randomised studies set a precedent for how we as a community should evaluate new technologies. Evaluation using case series or cohort studies have a role, but do not provide sufficiently robust evidence to convince national funding bodies to commission new technologies for use in the NHS.”