Here are a couple of possible candidates for that role, unfortunately I don't watch many anime of Chihayafuru's genre so none of these are great.
Sakakibara from Another. Hospital scene is in the first episode.
Kyōsuke Kamijō from Madoka. episode 3 and 4
Yō Satō from Bento. Episode 8, has the added benefit of being in a full body cast at one point making him completely unrecognizable as a backup plan.
Alma Tandouji from Sacred Seven, he isn't hospitalized but there is this research lab place later on in the series and I think he was there at one point being examined, kinda, maybe, possibly
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