The world's top medical technology companies are turning to robots to help with complex knee surgery, promising quicker procedures and better results in operations that often leave patients dissatisfied.
Demand for artificial replacement joints is growing fast, as baby boomers' knees and hips wear out, but for the past 15 years rival firms have failed to deliver a technological advance to gain them significant market share.
Now U.S.-based Stryker and Britain's Smith & Nephew believe that is about to change, as robots give them an edge.
Robots should mean less trauma to patients and faster recovery, although they still need to prove themselves in definitive clinical studies, which will not report results for a couple of years.
Fares Haddad, a consultant surgeon at University College London Hospitals, is one of the first in Britain to use the new robots and has been impressed. However, he agrees healthcare providers need decisive data to prove they are worth an investment that can be as much as $1 million for each robot.
"The main reason for using a robotic system is to improve precision and to be able to hit very accurately a target that varies from patient to patient," he said. "It is particularly useful in knees because they are more problematic (than hips) and there are a chunk of patients that aren't as satisfied as we would like with their knee replacement."
Satisfaction rates are only around 65 percent for knee operations, against 95 percent for hips, according to industry surveys.
The rival types of robots vary in cost and sophistication, assisting surgeons with precision image guidance for bone cutting and the insertion of artificial joints.