A knee-replacement implant, used in thousands of UK operations, was known to have a concerning failure rate eight years before it was finally withdrawn, the BBC has discovered.
Patients have told File on 4 Investigates how they were left immobile or addicted to painkillers after receiving the NexGen knee implant, because it ended up slipping out of place. Hundreds of people have now had to undergo a second corrective operation.
Knee surgeons say the implant's US manufacturer, Zimmer Biomet, took too long to acknowledge there was a problem with one particular component.
Zimmer Biomet says patient safety is its "top priority" and that its products are approved in accordance with the relevant regulations.
Debbie Booker from Southampton had an operation to replace her left knee in 2016.
