There were no differences between groups in favour of the gabapentin group for pain or physical function on POD 4 [ 95 % confidence interval ( CI ) : pain : -1.4 , 0.5 ; function : -6.3 , 2.0 ] , 6 weeks ( 95 % CI : pain : 0.1 , 1.9 ; function : -0.2 , 6.5 ) or 3 months ( 95 % CI : pain : -0.2 , 1.7 ; function : -2.2 , 4.3 ) after TKA .