Skip to main content

Table 2 Mean annual change of clinical variables in groups according to final knee flexion after TKA

From: A high degree of knee flexion after TKA promotes the ability to perform high-flexion activities and patient satisfaction in Asian population

Variable

Estimated marginal mean (95% CI)

Mean change/year (95% CI)

p for interaction with time

Preoperative

(n = 912)

2 years

(n = 912)

5 years

(n = 718)

10 year

(n = 261)

linear

quadratic

linear

quadratic

Knee flexion (°)

 Final knee flexion < 130

119.5 (114.6, 124.3)

123.0 (118.2, 127.8)

124.7 (119.8, 129.6)

118.2 (112.5, 123.8)

2.2 (1.6, 2.9)

−0.2 (− 0.3, − 0.2)

0.006

0.023

 Final knee flexion ≥130

131.4 (126.6, 136.2)***

134.6 (129.8, 139.3)***

137.3 (132.5, 142.1)***

136.6 (131.5, 141.7)***

1.9 (1.4, 2.3)

−0.1 (− 0.2, − 0.1)

Flexion contracture (°)

 Final knee flexion < 130

10.4 (8.2, 12.5)

3.3 (1.2, 5.4)

−2.1 (−4.2, 0.0)

2.8 (0.4, 5.2)

−4.2 (− 4.5, −3.9)

0.4 (0.3, 0.4)

n.s.

n.s.

 Final knee flexion ≥130

9.7 (7.6, 11.7)

3.2 (1.1, 5.2)

−1.9 (−4.0, 0.2)

2.0 (−0.2, 4.2)

−3.9 (− 4.1, − 3.7)

0.3 (0.3, 0.3)

Range of motion (°)

 Final knee flexion < 130

107.7 (100.2, 115.2)

117.4 (109.9, 124.8)

124.0 (116.5, 131.6)

114.3 (105.6, 123.1)

5.9 (4.8, 7.0)

−0.5 (− 0.7, − 0.4)

n.s.

0.028

 Final knee flexion ≥130

119.5 (112.1, 126.9)

127.7 (120.4, 135.1)

134.8 (127.4, 142.2)

132.5 (124.6, 140.4)**

4.8 (4.1, 5.5)

−0.4 (− 0.4, − 0.3)

Knee Society score

 Final knee flexion < 130

58.9 (52.4, 65.5)

85.7 (79.3, 92.1)

105.9 (99.4, 112.4)

86.2 (78.5, 94.0)

16.1 (15.0, 17.1)

−1.3 (− 1.5, − 1.2)

n.s.

n.s.

 Final knee flexion ≥130

59.2 (52.7, 65.6)

85.9 (79.6, 92.3)

106.2 (99.8, 112.6)

86.9 (80.1, 93.8)

16.0 (15.3, 16.7)

−1.3 (− 1.4, − 1.3)

Knee Society function score

 Final knee flexion < 130

50.3 (40.3, 60.3)

73.0 (63.2, 82.9)

87.2 (77.2, 97.3)

57.7 (45.9, 69.5)

14.0 (12.7, 15.4)

−1.3 (− 1.5, − 1.2)

0.007

n.s.

 Final knee flexion ≥130

50.7 (40.8, 60.6)

73.5 (63.6, 83.3)

90.1 (80.2, 100.0)

71.0 (60.4, 81.5)

13.7 (12.9, 14.6)

−1.2 (− 1.3, − 1.1)

Hospital for Special Surgery score

 Final knee flexion < 130

63.7 (57.5, 69.9)

83.8 (77.6, 89.9)

97.9 (91.7, 104.1)

78.8 (71.5, 86.0)

12.2 (11.4, 13.0)

−1.1 (− 1.2, − 1.0)

0.029

n.s.

  Final knee flexion ≥130

64.1 (58.0, 70.2)

84.7 (78.7, 90.8)

100.2 (94.1, 106.3)

84.8 (78.3, 91.3)

12.4 (11.8, 12.9)

−1.0 (− 1.1, − 1.0)

WOMAC (total)

 Final knee flexion < 130

39.9 (32.6, 47.1)

19.9 (12.7, 27.0)

4.9 (−2.4, 12.1)

20.0 (11.9, 28.1)

−12.0 (− 13.0, − 11.1)

1.0 (0.9, 1.1)

0.003

n.s.

 Final knee flexion ≥130

40.7 (33.5, 47.8)

18.8 (11.7, 26.0)

1.8 (−5.4, 8.9)

15.0 (7.5, 22.5)

−13.0 (− 13.6, − 12.4)

1.0 (1.0, 1.1)

WOMAC (pain)

 Final knee flexion < 130

6.4 (5.1, 7.6)

2.1 (0.9, 3.4)

−1.3 (−2.5, −0.0)

1.0 (−0.4, 2.4)

− 2.5 (− 2.7, − 2.3)

0.2 (0.2, 0.2)

n.s.

n.s.

 Final knee flexion ≥130

6.6 (5.4, 7.8)

2.1 (0.9, 3.3)

− 1.5 (− 2.7, − 0.3)

1.1 (− 0.2, 2.4)

−2.7 (− 2.8, − 2.6)

0.2 (0.2, 0.2)

WOMAC (stiffness)

 Final knee flexion < 130

3.2 (2.5, 3.9)

1.4 (0.7, 2.1)

0.0 (− 0.7, 0.7)

1.0 (0.2, 1.8)

−1.1 (− 1.2, − 1.0)

0.1 (0.1, 0.1)

n.s.

0.027

 Final knee flexion ≥130

3.3 (2.6, 4.1)

1.3 (0.6, 2.0)

−0.2 (− 0.9, 0.5)

1.1 (0.4, 1.8)

−1.2 (− 1.3, − 1.1)

0.1 (0.1, 0.1)

WOMAC (physical function)

 Final knee flexion < 130

30.8 (24.9, 36.6)

16.2 (10.5, 21.9)

5.7 (−0.1, 11.5)

18.6 (12.0, 25.2)

−8.8 (−9.6, −8.0)

0.76 (0.67, 0.85)

0.001

n.s.

 Final knee flexion ≥130

31.0 (25.3, 36.7)

15.2 (9.5, 20.9)

3.0 (−2.7, 8.7)

13.3 (7.3, 19.3)

−9.4 (−9.9, −8.9)

0.77 (0.71, 0.82)

  1. WOMAC Western Ontario and McMaster Universities Osteoarthritis Index, n.s. not significant
  2. ***, p < 0.001; **, p < 0.01; *, p < 0.05, compared two group at each point