At 6 weeks after surgery there were no significant differences between usual care and HEP , respectively , for pain ( 7.4 and 7.2 ; 95 % CI mean difference [ MD ] -0.7 , 0.9 ) , physical function ( 22.5 and 22.4 ; 95 % CI MD -2.5 , 2.6 ) , knee flexion ( 96 and 97 ; 95 % CI MD -4 , 2 ) , knee extension ( -7 and -6 ; 95 % CI MD -2 , 1 ) , or the 50-foot walk time ( 12.9 and 12.9 seconds ; 95 % CI MD -0.8 , 0.7 seconds ) .