Table 7 Means and standard deviations of FJS-12 individual questionnaires and total scores at baseline and follow-up, and bias, its standard error and 95% confidence intervals after bootstrapping for N = 200 and N = 1000

FJS-12 Q01 Baseline

Mean

3.17

-0.02

0.24

2.75—3.50

3.17

0.01

0.22

2.75—3.58

Standard deviation

1.17

-0.00

0.22

0.88—1.43

1.17

-0.03

0.16

0.88—1.39

FJS-12 Q01 Follow-up

Mean

3.38

-0.03

0.22

3.00—3.67

3.38

0.01

0.23

2.92—3.79

Standard deviation

1.17

-0.02

0.15

0.88—1.41

1.17

-0.04

0.17

0.84—1.38

FJS-12 Q02 Baseline

Mean

3.33

0.01

0.25

2.88—3.87

3.33

0.01

0.24

2.88—3.79

Standard deviation

1.20

-0.05

0.15

0.93—1.37

1.20

-0.04

0.14

0.98—1.34

FJS-12 Q02 Follow-up

Mean

3.25

0.00

0.26

2.79—3.67

3.25

0.01

0.25

2.75—3.75

Standard deviation

1.26

-0.05

0.15

1.01—1.42

1.26

-0.04

0.14

1.01—1.41

FJS-12 Q03 Baseline

Mean

3.29

-0.02

0.28

2.75—3.72

3.29

0.01

0.27

2.75—3.79

Standard deviation

1.37

-0.04

0.13

1.20—1.47

1.37

-0.04

0.13

1.14—1.52

FJS-12 Q03 Follow-up

Mean

3.13

0.00

0.28

2.67—3.62

3.13

0.01

0.27

2.63—3.67

Standard deviation

1.39

-0.04

0.14

1.19—1.51

1.39

-0.04

0.13

1.16—1.54

FJS-12 Q04 Baseline

Mean

2.63

0.00

0.29

2.17—3.17

2.63

0.01

0.28

2.04—3.13

Standard deviation

1.44

-0.02

0.10

1.23—1.59

1.44

-0.03

0.12

1.25—1.58

FJS-12 Q04 Follow-up

Mean

3.00

0.03

0.29

2.37—3.59

3.00

0.02

0.30

2.38—3.63

Standard deviation

1.47

-0.05

0.13

1.30—1.55

1.47

-0.04

0.14

1.27—1.60

FJS-12 Q05 Baseline

Mean

2.96

0.01

0.27

2.46—3.46

2.96

0.02

0.27

2.42—3.50

Standard deviation

1.40

-0.03

0.13

1.14—1.56

1.40

-0.03

0.13

1.18—1.53

FJS-12 Q05 Follow-up

Mean

3.21

-0.01

0.24

2.79—3.67

3.21

0.01

0.24

2.79—3.63

Standard deviation

1.22

-0.04

0.14

0.97—1.38

1.22

-0.03

0.14

0.98—1.38

FJS-12 Q06 Baseline

Mean

3.88

0.00

0.23

3.50—4.25

3.88

0.01

0.23

3.42—4.33

Standard deviation

1.19

-0.04

0.20

0.78—1.47

1.19

-0.05

0.20

0.81—1.44

FJS-12 Q06 Follow-up

Mean

3.92

-0.02

0.18

3.67—4.17

3.92

0.00

0.20

3.54—4.29

Standard deviation

1.02

-0.03

0.15

0.76—1.24

1.02

-0.04

0.17

0.75—1.23

FJS-12 Q07 Baseline

Mean

3.25

0.01

0.24

2.88—3.75

3.25

0.01

0.24

2.79—3.67

Standard deviation

1.19

-0.03

0.14

0.96—1.35

1.19

-0.04

0.15

0.92—1.36

FJS-12 Q07 Follow-up

Mean

3.54

0.02

0.24

3.06—4.03

3.54

0.01

0.23

3.04—4.00

Standard deviation

1.18

-0.07

0.21

0.75—1.40

1.18

-0.05

0.20

0.83—1.38

FJS-12 Q08 Baseline

Mean

3.75

0.00

0.23

3.29—4.13

3.75

0.01

0.23

3.29—4.21

Standard deviation

1.19

-0.04

0.17

0.86—1.44

1.19

-0.04

0.18

0.88—1.38

FJS-12 Q08 Follow-up

Mean

4.13

0.00

0.19

3.79—4.50

4.13

0.00

0.20

3.75—4.50

Standard deviation

0.99

-0.05

0.19

0.66—1.20

0.99

-0.04

0.20

0.66—1.23

FJS-12 Q09 Baseline

Mean

3.92

0.00

0.20

3.54—4.25

3.92

0.01

0.22

3.50—4.33

Standard deviation

1.10

-0.02

0.17

0.76—1.35

1.10

-0.04

0.18

0.76—1.34

FJS-12 Q09 Follow-up

Mean

4.00

0.00

0.16

3.74—4.25

4.00

0.00

0.18

3.67—4.29

Standard deviation

0.89

-0.04

0.20

0.55—1.12

0.89

-0.04

0.22

0.54—1.14

FJS-12 Q10 Baseline

Mean

3.63

-0.01

0.20

3.29—3.96

3.63

0.01

0.22

3.17—4.08

Standard deviation

1.14

-0.04

0.17

0.79—1.37

1.14

-0.04

0.18

0.83—1.34

FJS-12 Q10 Follow-up

Mean

3.58

0.01

0.19

3.17—3.92

3.58

0.00

0.21

3.21—3.96

Standard deviation

1.06

-0.06

0.18

0.65—1.26

1.06

-0.04

0.19

0.70—1.29

FJS-12 Q11 Baseline

Mean

3.33

-0.01

0.20

3.00—3.67

3.33

0.01

0.22

2.92—3.75

Standard deviation

1.09

-0.03

0.15

0.78—1.31

1.09

-0.04

0.15

0.83—1.25

FJS-12 Q11 Follow-up

Mean

3.50

0.01

0.21

3.13—3.88

3.50

0.01

0.22

3.08—3.92

Standard deviation

1.10

-0.05

0.17

0.76—1.29

1.10

-0.05

0.17

0.85—1.25

FJS-12 Q12 Baseline

Mean

3.29

0.00

0.20

2.98—3.67

3.29

0.01

0.22

2.88—3.71

Standard deviation

1.08

-0.03

0.15

0.78—1.32

1.08

-0.04

0.15

0.83—1.25

FJS-12 Q12 Follow-up

Mean

3.50

0.02

0.24

3.00—4.02

3.50

0.02

0.25

2.97—4.04

Standard deviation

1.25

-0.05

0.15

1.00—1.40

1.25

-0.04

0.15

1.03—1.38

FJS-12 Total Baseline

Mean

40.80

0.06

4.99

29.55—50.70

40.80

-0.31

4.91

32.47—48.70

Standard deviation

25.28

-0.56

3.32

18.26—30.57

25.28

-0.76

3.36

19.54—29.29

FJS-12 Total Follow-up

Mean

37.24

-0.06

4.46

29.13—46.58

37.24

-0.23

4.68

28.65—45.58

Standard deviation

23.63

-1.00

3.51

17.08—27.17

23.63

-0.75

3.70

17.55—28.08