Yes, but it's an entirely different animal to the old Biopace, and he wasn't riding a fixed gear. His could be tuned through very small increments to find the precise optimal mounting position to even out any issues he has with his pedal stroke. Biopace was very limited, and the recommended mounting position was to make pedaling seem easier for the couch potato masses, not optimized for spin, power, etc.

The reason most pros don't use them is that they don't feel they have issues to resolve. I doubt they have all taken the time to perform the exhaustive testing necessary to determine whether they actually could benefit or not. However, the companies currently promoting these pieces don't have the promotions budget necessary to make serious inroads into the pro peloton.

You would see more pros on them if someone with them started consistently running away from everyone. On a road bike, I would be curious to play with the new Rotor rings. On fixed, no.