In the kdrama I Miss You, one male lead (Yoo Seung Ho) does have a walking disability (he has to use a cane)... Unfortunately he is more of the other love interest rather than the main lead. As of now, this drama is still airing..
Also in the drama Dream High, one of the main leads develops a hearing disability, but that's later in the story.
In Nice Guy, the main lead has some sort of brain clot/aneurism, after several episodes, but he refuses the surgery and often lives in pain.
I hope this helps!