Benefits and risks

Information for the public

When NICE looked at the evidence, it decided that there was not enough evidence to show that this procedure works well or is safe. The study that NICE looked at involved a total of 99 patients. There were also reports about the procedure in 4 other patients.

Generally, the study showed significant improvements in patients' pain, physical function (such as walking or standing) and stiffness while carrying out everyday activities. Their knee pain became much less severe during the year after the procedure.

In the first 6 weeks after the procedure the range of movement of the knee reduced. It gradually returned to its usual range 1 year after the procedure.

All devices were implanted and started working successfully in the 99 patients.

The studies showed that the risks of the procedure included:

the device breaking and needing removal in 1 patient
infection of the wound in 1 patient, needing removal of the device
pain, needing removal of the device in 4 patients. Two other patients reported pain that came back within 6 months of the procedure.

For 6 patients there was no improvement in symptoms, resulting in further surgery.

NICE was also told about some other possible risks: tissue irritation, the device pressing on surrounding bone or tissues, the device not working properly, or the device breaking and needing removal.

If you want to know more about the studies, see the guidance. Ask your health professional to explain anything you don't understand.