You’re quite right, that is pedantic….. . More seriously, you’re bang right, it was a tendon from the hamstring. It was also about 20 years ago, so I’m sure the procedure and recovery has moved on since then.
As you say, we don’t know what he’s done and professional sportsmen will I’m sure be handled somewhat differently to the average NHS punter. That said, I don’t think there is any harm in folk sharing their own experiences if it help others to understand that the road back from significant knee injuries can be a long one.