The sentence is not mine. I got it from a magazine.
I find the sentence unclear and ambiguous, which is the reason for this post. I am even more puzzled when a friend of mine told me that the sentence is OK.
In this case I would ask your friend to explain what the sentence means in his own words. Maybe he just interprets it in a certain way. Would it be possible to bring your friend on the forum here?
According to my friend, the writer fell down during his stay in the hospital, and that was a few days before he resumed work. (Do you think his explanation makes sense?)
Could you let me know if the original sentence is ambiguous or I was unable to understand the meaning of the sentence due to the fact my English is not good enough?