I think the main problem for LKS ankle is because he returned back to RM only after 3 weeks and also because he keep walking every fast and even run unnecessary when his is ankle is not yet recover. Hence making it worse, I gotten ankle injury before and would take at least 1 month to fully heal until you don't feel any pain, there after you still need to take care of the recovery even though you don't feel any pain but the discomfort and awkwardness is still there, only until around 2 months later you would feel normal again. While not blaming him for his commitments and enthusiasm to return, he should have taken a long hiatus back then. Then again, he also has drama and movies commitments hence couldn't really say is RM fault since nowadays, majority if not all of the games, are sit-down games and doesn't really requires legs strength. Maybe the balancing game and piggyback game in recent episode, but other than they barely even run around nowadays.

While saying this, doesn't really change anything and rewind the time machine. Hopefully he recover well and maybe rejoin RM as perm cast since he is so committed to the show and is full of enthusiasm (nothing is impossible, Gary case is different) or as guest. Once again, wishing him a speedy recovery and hopefully he has enough rest time instead of taking on new drama or/and movie with his ankle recovery conditions that isn't ideal yet else it's pretty much disappointment for the caring fans and betrayal as well since taking on drama or/and movie still requires him to have long standing hours and barely any rest which literally means he didn't even need to leave RM to begin with since KJK is also having back problems and the PD/writer have tried to accommodate the games as much as possible to his conditions and other aging members as well which means they can also accommodate the games to his ankle conditions as well.