I've been commuting on fixed gear bike with brakkless installed for at least last 10 years and it's the best bike for the city imo. And my knees are doing absolutely fine.
There's still hope.
@Tijmen started
London Fixed Gear and Single-Speed is a community of predominantly fixed gear and single-speed cyclists in and around London, UK.
This site is supported almost exclusively by donations. Please consider donating a small amount regularly.
There's still hope.