Table 4

Rates of minimum clinically important difference achievement by arthroplasty group.

Outcome Measure	6 wk	12 wk	6 mo	1 y	2 y	Overall
Oswestry Disability Index
No arthroplasty	36.6%	44.2%	55.1%	60.6%	62.7%	65.1%
Arthroplasty	42.9%	52.6%	78.9%	78.6%	44.4%	72.0%
P value^{^a}	0.573	0.479	0.035	0.172	0.296	0.477
12-Item Short Form Physical Component Summary
No arthroplasty	30.4%	48.1%	57.1%	68.0%	64.0%	69.4%
Arthroplasty	33.3%	55.6%	47.1 %	66.7%	44.4%	69.6%
P value^{^a}	0.796	0.586	0.434	0.917	0.256	0.987
Patient-Reported Outcomes Measurement Information System Physical Function
No arthroplasty	15.8%	29.1%	48.2%	51.1%	56.0%	59.3%
Arthroplasty	20.0%	30.0%	33.3%	30.0%	42.9%	63.6%
P value^{^a}	0.735	0.950	0.386	0.199	0.505	0.774
VAS back
No arthroplasty	67.7%	70.9%	73.1%	75.4%	71.6%	84.1%
Arthroplasty	65.0%	55.6%	66.7%	76.9%	62.5%	79.2%
P value^{^a}	0.799	0.183	0.561	0.902	0.598	0.539
VAS leg
No arthroplasty	62.5%	65.5%	63.6%	64.6%	59.9%	79.6%
Arthroplasty	38.1%	47.4%	57.9%	57.1%	55.6%	72.0%
P value^{^a}	0.029	0.119	0.626	0.587	0.395	0.389