Table 1 Characteristics of included studies (O operative, N non-opreative)

Rangan et al. (2015)

67.42/66.12

114/117

77.6/76.0

24

86

Boons et al. (2012)

79.9/76.4

25/25

92/96

24

94

Fjalestad et al. (2010, 2012); Fjalestad and Hole (2014)

72.2/73.1

25/25

80/94

12

98.0

Olerud et al. (2011a, b)

72.9/74.9

30/30

80/83

24

88.3

Olerud et al. (2011a, b)

75.8/77.5

27/28

85/86

24

89.1

Stableforth (1984)

65.6/70.1

16/16

75/81.3

6–48

93.8

Zyto et al. (1997)

73/75

20/20

90/85

36–60

72.5