Table 1. Patient Demographics.

	Total	Group 1	Group 2	Group 3	Group 4	p value
Number of cases (number of patients)	627 (445)	351 (264)	189 (121)	59 (42)	28 (18)
Gender
Male	34 (30)	22 (21)	9 (6)	3 (3)	0 (0)
Female	593 (415)	329 (243)	180 (115)	56 (39)	28 (18)
Age	71.8±6.5	71.4±6.4	72.3±6.8	72.1±6.3	70.0±5.3	0.511
Weight (kg)	61.8±9.2	62.2±9.3	61.7±9.0	60.9±8.9	59.8±8.6	0.4575
Height (cm)*	150±6	152±7	151±7	147±6	147±5	<0.0001
Body mass index	27.2±3.7	27.1±3.6	27.3±3.8	28.1±3.6	27.6±3.8	0.2328
Number of diagnosis
OA	622 (441)	347 (261)	188 (120)	59 (42)	28 (18)
ON	2 (2)	1 (1)	1 (1)	0 (0)	0 (0)
RA	3 (2)	3 (2)	0 (0)	0 (0)	0 (0)
Preoperative ROM (degree)*	126.5±19.0	128.1±18.6	126.5±17.7	120.9±21.3	118.2±26.8	0.0052
Preoperative pain score*	32.1±10.6	33.8±11.2	30.6±9.6	29.5±8.6	26.6±12.2	<0.0001
Preoperative functional score	47.2±7.9	47.9±7.7	46.9±7.8	45.9±8.9	45.0±9.2	0.0913
Preoperative HSS score*	64.9±7.6	65.7±7.2	64.9±7.8	63.0±7.3	58.7±10.5	<0.0001
Preoperative femorotibial angle (degree)	-5.4±1.4	-2.4±1.4	-7.0±1.3	-11.9±1.2	-17.5±2.9	<0.0001

OA, osteoarthritis; ON, osteonecrosis; RA, rheurmatoid arthritis; ROM, range of motion; HSS, hospital for special surgery.

Femorotibial angle (negative values=varus; positive values=valgus); p value=analysis of variance.

^*p<0.05=significant difference among the groups (Table 2).