Table 2 Patient-reported outcomes (PROs) preoperative and 1-year postoperative by education level

WOMAC Pain

n=340

n=306

n=317

 Preoperative

36.0 (18.6)

39.2 (16.0)

43.8 (17.1)

 1-year postoperative

84.3 (19.1)

87.6 (17.3)

89.6 (16.4)

 Gain

48.3 (23.3)

48.4 (20.3)

45.9 (19.2)

 Effect size, Cohen’s d

2.6

2.9

2.7

WOMAC Function

n=328

n=295

n=306

 Preoperative

36.2 (19.1)

39.7 (17.7)

45.5 (16.9)

 1-year postoperative

76.3 (22.8)

82.0 (19.7)

85.6 (17.1)

 Gain

40.1 (24.8)

42.2 (22.1)

40.1 (20.0)

 Effect size, Cohen’s d

1.9

2.3

2.4

SF-12 PCS

n=326

n=294

n=306

 Preoperative

33.1 (7.6)

33.9 (7.4)

34.3 (7.9)

 1-year postoperative

42.9 (9.3)

45.6 (9.5)

47.1 (9.5)

 Gain

9.8 (10.2)

11.7 (10.0)

12.8 (10.6)

 Effect size, Cohen’s d

1.2

1.4

1.5

SF-12 MCS

n=326

n=294

n=306

 Preoperative

41.9 (11.5)

44.7 (10.6)

47.5 (10.3)

 1-year postoperative

46.4 (11.1)

48.5 (9.8)

49.2 (10.0)

 Gain

4.6 (11.4)

3.8 (10.2)

1.7 (10.3)

 Effect size, Cohen’s d

0.5

0.4

0.2