File on 4 Investigates reveals how surgeons had raised concerns about a faulty replacement knee eight years before its US manufacturer finally decided to withdraw it from use.

Knee replacement surgery is one of the most common operations carried out by the NHS, with over 100,000 procedures carried out each year. It’s a surgical success story - but things can go wrong.

Around 10,000 problematic 'NexGen' knee implants, made by the US medical tech giant Zimmer Biomet, were fitted into UK patients over the past decade or so, until they were withdrawn in 2022.

But File on 4 Investigates exclusively reveals that warnings were given to both the company and the government regulator eight years before the product was recalled.

Reporter Adrian Goldberg talks to patients who had to endure the agony of new corrective surgery and orthopaedic surgeons whose reputations were thrown into doubt.

Reporter: Adrian Goldberg Producer: Jim Booth Story and Development Producer: Nazrin Wilkinson Technical Producer: Nicky Edwards Production Coordinator: Tim Fernley Editor: Richard Fenton-Smith