Table 1 Comparisons of patient and surgical factors between groups

Age (years)

72.1 ± 7.4

69.1 ± 7.1

0.015^c

Sex (male:female)

12:55

9:66

0.352^d

Height (cm)

152.1 ± 8.6

151.1 ± 6.2

0.421^c

Weight (kg)

59.9 ± 10.9

63.0 ± 8.5

0.061^c

BMI (kg/m²)

25.4 ± 4.8

27.6 ± 3.3

0.002^c

Preoperative flexion contracture (degrees)

4.3 ± 8.8

5.2 ± 8.6

0.551^c

Preoperative further flexion (degrees)

137.0 ± 7.6

135.9 ± 9.4

0.427^c

Preoperative mechanical axis (degrees)

Varus 8.4 ± 6.6

Varus 8.2 ± 5.9

0.855^c

Postoperative mechanical axis (degrees)

0.5 ± 2.1

0.4 ± 2.0

0.752^c

Preoperative patellar tilt (degrees)

3.7 ± 3.3

3.8 ± 3.6

0.876^c

Postoperative patellar tilt (degrees)

2.3 ± 3.4

5.7 ± 4.5

0.017^c

Preoperative patellar displacement (mm)

4.1 ± 2.6

6.0 ± 3.5

<0.001^c

Postoperative patellar displacement (mm)

1.1 ± 1.5

4.0 ± 2.2

<0.001^c

Preoperative Insall-Salvati ratio

0.9 ± 0.1

0.9 ± 0.1

0.520^c

Preoperative Blackburne-Peel ratio

1.3 ± 0.1

1.5 ± 0.2

0.108^c

Preoperative patellar thickness (mm)

21.5 ± 2.0

21.5 ± 1.5

0.832^c

Postoperative patellar thickness (mm)

21.4 ± 1.5

21.3 ± 1.2

0.711^c

MCL release (yes:no)

3:64

24:51

<0.001^d

PCL release (yes:no)

10:57

15:60

0.511^d

Femoral valgus cut angle (degrees)

6.3 ± 0.8

6.0 ± 0.8

0.034^c

Distal femoral cut rotation (degrees)

4.6 ± 1.4

4.5 ± 1.6

0.686^c