They didn't spell anything wrong. I was hoping that DMC was joking, and I'm still going to give him credit for that being a joke.
"Patella" is the kneecap. "Patellar" means relating to the kneecap - just like "stellar" means relating to the stars.
The patellar tendon is technically an extension of the quadriceps. So it connects the quadriceps to the tibia (shinbone), but with the kneecap sort of embedded in the middle. So Lee's injury is very close to the place that Tony was injured. The thing is, those injuries are a LOT more common in older players. The quadriceps tendon and the patellar tendon are designed to take a lot of abuse, because of what they have to do. When a guy goes down from that injury, and there's no obvious knee-to-knee or long-term tendonitis, it often means that there is at least some light tearing.