Hospitalised, a number need help to get out of bed (4,2)
I believe the answer is:
laid up
'hospitalised' is the definition.
(thesaurus)
'a number need help to get out of bed' is the wordplay.
'a number' becomes 'L' (fifty in Roman numerals).
'need' says to put letters next to each other.
'help' becomes 'aid' (synonyms).
'to get' means one lot of letters go next to another.
'out of bed' becomes 'up' (synonyms).
'l'+'aid'+'up'='LAID-UP'
(Other definitions for laid up that I've seen before include "Confined to bed by illness" , "Stayed off-green" , "Stored, preserved" , "Bedridden" , "Saved" .)