Joint operation all the rage on work posting (3,11)
I believe the answer is:
hip replacement
'joint operation' is the definition.
(operation to replace a joint)
'all the rage on work posting' is the wordplay.
'all the rage' becomes 'hip' (both can mean fashionable).
'on' becomes 're' ('on' can be mean 'with reference to').
'work posting' becomes 'placement' (placement can mean a job posting).
'hip'+'re'+'placement'='HIP REPLACEMENT'
(Other definitions for hip replacement that I've seen before include "Inserted joint" , "Joint operation" .)