Table 3 Pre- and post-operative radiographic features

 Pre-operative

15.9 ± 12.6^a

5.4 ± 8.4

6.9 ± 6.1^a

− 1.6 ± 5.1

 24-month post-operative

59.7 ± 10.1^b

61.2 ± 7.1^a

51.4 ± 8.5^b,c

61.3 ± 7.6^a

 Pre-operative

182.9 ± 3.9

185.0 ± 3.8

186.7 ± 1.2

188.5 ± 2.9

 24-month post-operative

172.9 ± 3.4^b

171.3 ± 2.5^a

176.3 ± 2.0^b,c

171.1 ± 2.9^a

 Pre-operative

82.4 ± 2.9

82.4 ± 2.8

80.2 ± 1.6

80.9 ± 2.9

 24-month post-operative

90.3 ± 2.4 ^b

91.7 ± 2.1^a

88.2 ± 1.6^b,c

92.8 ± 2.0^a

 Pre-operative

88.6 ± 1.2

88.9 ± 1.3

88.7 ± 1.2

89.2 ± 1.2

 24-month post-operative

88.1 ± 1.0

88.6 ± 1.6

88.4 ± 0.9

89.5 ± 1.3

 Pre-operative

2.8 ± 0.9^a

6.4 ± 1.7

3.6 ± 0.3^a

7.5 ± 1.6

 24-month post-operative

2.2 ± 1.3^b

1.2 ± 0.9^a

3.4 ± 1.1 ^c

1.4 ± 1.1^a

 Pre-operative

− 1.3±1.6 ^a

− 8.0 ± 2.9

− 2.4 ± 1.1^a

− 9.9 ± 2.6

 24-month post-operative

− 1.0±1.8 ^c

5.9 ± 2.5^a

− 2.3 ± 1.4^c

5.9 ± 3.2^a

 Pre-operative

83.9 ± 1.9

82.4 ± 2.4

 24-month post-operative

81.2 ± 2.4^b

82.0 ± 3.2