Table 2.

Mean change and responsiveness in Activity Assessment Scale score from baseline to 2-weeks postoperatively by change in SF-36 Physical Function

SF-36 Physical Function	N Total=161	mean (SD) at baseline	mean (SD) at 2 week follow-up	Mean AAS Change (SD)	Effect size	P-value*
Improved	32	72.0 (19.5)	82.7 (14.0)	+ 8.2 (25.5)	0.42	<0.0001
No Change	23	84.0 (18.1)	85.5 (19.4)	−2.2 (29.0)	−0.12
Worse	106	85.5 (15.2)	75.2 (21.1)	−10.8 (22.5)	−0.71

^*F-statistics testing whether AAS change differs among the three categories according to SF-36 physical functioning subscale.

^#For baseline < 40: +/− 2 points for “no change” category, > 2 for “improving”, < −2 for “worsening”;

For baseline ≥ 40: +/− 3 points for “no change” category, > 3 for “improving”, < −3 for “worsening”.