A little work needed in joint (4)
I believe the answer is:
knee
'joint' is the definition.
(knee joint is a kind of joint)
'a little work needed in' is the wordplay.
'in' indicates the answer is hidden within the clue.
'KNEE' is hidden in the letters of 'little work needed'.
(Other definitions for knee that I've seen before include "This is capped by the patella" , "Hinge between the thigh and the shin" , "Human joint" , "Joint protected by the patella" , "Leg hinge" .)