Table 3 Pearson correlation coefficients between HKA and 6DOF for the whole cohort and the various groups

Flexion/extension angle

Varus/valgus angle

Internal/external rotation

Anterior-posterior displacement

Superior-inferior displacement

Medial-lateral displacement

Whole

Pearson

-0.11

0.14

0.00

-0.19*

-0.05

-0.16

 N = 179

Sig

0.13

0.06

0.99

0.01

0.52

0.84

Pre

Pearson

-0.10

0.20

-0.20

-0.22

-0.08

0.17

 N = 99

Sig

0.32

0.05

0.85

0.03

0.45

0.87

post

Pearson

-0.19

0.01

-0.01

-0.06

-0.16

-0.15

 N = 80

Sig

0.87

0.95

0.98

0.57

0.17

0.18

A

Pearson

0.29*

-0.74

0.12

0.10

0.24

0.05

 N = 49

Sig

0.042

0.61

0.41

0.50

0.09

0.71

B

Pearson

-0.09

0.23

-0.06

-0.31*

-0.17

-0.04

 N = 50

Sig

0.52

0.10

0.69

0.03

0.25

0.78

C

Pearson

0.17

0.03

-0.05

-0.06

-0.10

0.14

 N = 48

Sig

0.24

0.84

0.72

0.69

0.52

0.34

D

Pearson

-0.10

0.02

0.00

-0.19

-0.20

-0.26

 N = 32

Sig

0.58

0.91

0.99

0.31

0.28

0.15