Does ethnicity and education influence preoperative disability and expectations in patients undergoing total knee arthroplasty?

Table 3 Significance of duration of education n (%)

	Education 0-9 yr	Education 9-12 yr	Education > 12 yr	P value (adjusted)
Baseline characteristics
BMI, mean ± SD	28.7± 5	30.0 ± 6	30.5 ± 5	< 0.001 (0.007)
Age, mean ± SD	64.8 ± 10	67.8 ± 10	67.7 ± 11	< 0.001 (0.005)
Gender
Male	92 (36.1)	159 (42.9)	54 (26.6)	< 0.001 (0.003)
Female	163 (63.9)	212 (57.1)	149 (73.4)
Ethnicity
Majority ethnicity	248 (97.3)	360 (97)	156 (76.8)	< 0.001 (< 0.001)
Minority ethnicity	7 (2.7)	11 (3)	47 (23.2)
Smoking:
Non-smoker	155 (60.8)	207 (55.8)	123 (60.6)	0.003 (0.017)
Former smoker	74 (29)	100 (27)	37 (18.2)
Active smoker	26 (10.2)	64 (17.3)	43 (21.2)
Preoperative level of function and symptoms
Walking aid outside the home	198 (77.6)	273 (73.6)	119 (58.6)	0.005 (0.002)
None	35 (13.7)	55 (14.8)	41 (20.2)
One cane	11 (4.3)	12 (3.2)	10 (4.9)
Two canes	10 (3.9)	27 (7.3)	32 (15.8)
Wheeled walker housebound	1 (0.4)	4 (1.1)	1 (0.5)
Oxford knee score, mean ± SD	24.6 ± 8	23.8 ± 7	21.5 ± 8	< 0.001 (< 0.001)
Knee pain during activity1, median (range)	59 (0:99)	63 (0:100)	67 (6:100)	< 0.001 (0.002)
Quality of life before surgery1, median (range)	45 (0:100)	47 (0:100)	50 (0:100)	0.634 (3.170)
Level of symptoms before surgery1, median (range)	51 (0:100)	50 (0:100)	50 (0:100)	0.634 (3.171)
Preoperative expectations
Expectations to knee pain caused by use of hip 1 yr after surgery1, median (range)	4 (0:95)	2 (0:96)	2 (0:100)	0.003 (0.008)
Expectations to quality of life 1 yr after surgery1, median (range)	90 (0:100)	94 (0:100)	96 (0:100)	< 0.001 (0.002)
Expectations to level of symptoms 1 yr after surgery1, median (range)	4 (0:82)	2 (0:99)	2 (0:99)	< 0.001 (0.001)
Postoperative level of function and symptoms:
Oxford knee score, median (range)	40 (8.0:47.0)	37 (3.0:48.0)	37.5 (7.0:48.0)	0.240 (0.960)
Knee pain during activity, Post-OP1, median (range)	12 (0.0:90.0)	20 (0.0:100.0)	26 (0.0:97.0)	0.002 (0.006)
Quality of life after surgery1, median (range)	77.5 (13.0:98.0)	70 (0.0:100.0)	69 (0.0:100.0)	0.055 (0.219)
Level of symptoms after surgery1, median (range)	21 (0.0:94.0)	23 (0.0:100.0)	31 (0.0:95.0)	0.182 (0.728)
Difference in outcome parameters:
Difference in Pain1, median (range)	8 (-11.0:84.0)	15 (-90.0:100.0)	21 (-48.0:97.0)	0.012 (0.069)
Difference in Quality of life Post-OP1, median (range)	-7 (-67.0:95.0)	-20 (-100.0:98.0)	-18 (-99.0:98.0)	0.003 (0.017)
Difference in level of symptoms1, median (range)	15 (-14.0:89.0)	17 (-56.0:100.0)	18 (-41.0:95.0)	0.532 (3.193)

¹Visual analogue scale 0-100. BMI: Body mass index.