I read here somewhere earlier that Nagaoka's injury was to her ankle. Do you have other information? I had assumed it was an injury to her knee because of how long she's been out (along with the notion--I'm not a doctor--that knee injuries are worse than ankle injuries).
That's what's weird to me. Knee injuries in general indeed take much longer to recover (ACL rupture for example takes 6 months mininum compared to 2-3 weeks for ankle twists), so I assumed that was Nagaoka's injury as well. But it's been waaay too long already, she's gotta have a chronic injury at this point...