Table 2 Matched patient outcomes scores:

WOMAC index score

 Preoperative, mean (SD) [range]

44.7 (13.1) [25.0–66.0]

57.1 (5.9) [45.0–68.0]

  0.014

47.1 (12.1) [25.0–66.0]

54.4 (5.9) [45.0–64.0]

  0.095

 POD 2, mean (SD) [range]

66.1 (7.7) [56.0–79.0]

88.0 (4.7) [78.0–96.0]

 < 0.001

70.0 (6.6) [63.0–79.0]

87.5 (4.9) [78.0–94.0]

 < 0.001

 POD 15, mean (SD) [range]

48.4 (6.1) [38.0–59.0]

65.9 (6.0) [57.0–78.0]

 < 0.001

51.0 (5.8) [46.0–59.0]

65.3 (5.9) [57.0–78.0]

 < 0.001

 POD 40, mean (SD) [range]

26.8 (2.0) [24.0–30.0]

29.0 (2.2) [24.0–35.0]

 < 0.001

26.4 (2.4) [24.0–30.0]

29.3 (2.0) [27.0–33.0]

  0.020

 12 months, mean (SD) [range]

25.5 (1.7) [24.0–28.0]

26.1 (1.5) [24.0–28.0]

  0.153

25.1 (1.6) [24.0–28.0]

26.3 (1.5) [24.0–28.0]

  0.112

ROM (°)

 Immediately after surgery, mean (SD) [range]

78.1 (10.9) [50.0–100.0]

40.2 (13.3) [10.0–70.0]

 < 0.001

75.7 (6.1) [65.0–80.0]

40.2 (13.9) [10.0–65.0]

 < 0.001

 POD 2, mean (SD) [range]

90.3 (10.1) [80.0–110.0]

51.4 (14.4) [20.0–80.0]

 < 0.001

85.0 (4.1) [80.0–90.0]

51.7 (15.2) [20.0–75.0]

 < 0.001

 POD 15, mean (SD) [range]

101.9 (10.0) [90.0–120.0]

91.3 (5.6) [80.0–100.0]

 < 0.001

97.1 (4.9) [90.0–105.0]

90.0 (5.9) [80.0–100.0]

  0.014

 POD 40, mean (SD) [range]

129.4 (5.1) [120.0–135.0]

110.6 (6.2) [90.0–120.0]

 < 0.001

126.4 (5.6) [120.0–135.0]

109.5 (6.3) [100.0–120.0]

 < 0.001

 12 months, mean (SD) [range]

128.1 (6.2) [110.0–135.0]

115.3 (7.6) [100.0–130.0]

 < 0.001

127.9 (4.9) [120.0–135.0]

116.4 (8.2) [100.0–130.0]

  0.003

Satisfaction questionnaire

 Very satisfied (%)

15 (83.3)

56 (71.8)

  0.712

5 (71.4)

15 (71.4)

  1.000

 Satisfied (%)

3 (16.7)

17 (21.8)

2 (28.6)

5 (23.8)

 Not completely satisfied (%)

0 (0)

5 (6.4)

0 (0)

1 (4.8)