Effect of hip disease regularly reenacted (9)
I believe the answer is:
influence
'effect' is the definition.
(I've seen this before)
'hip disease regularly reenacted' is the wordplay.
'hip' becomes 'in' (I've seen this in other clues).
'disease' becomes 'flu' (flu is a kind of disease**).
'regularly' means one should take alternating letters (regularly take one letter, leave next etc.).
The alternating letters of 'reenacted' are 'ence'.
'in'+'flu'+'ence'='INFLUENCE'
'of' is the link.
(Other definitions for influence that I've seen before include "Pull, clout" , "Agency" , "Clue in fen (anag.)" , "The prestige and power to affect others" , "Weight" .)