Table 1 Preoperative demographics between elderly patients (aged ≥75 years) and nonelderly patients (aged < 75 years)

Number of knees

48

63

Gender (female/male)

29/19

46/17

0.219

Diagnosis (OA/ON)

42/6

49/14

0.220

Age (years)

79.3 (3.1)

66.6 (5.6)

< 0.001*

Body mass index (kg/m²)

24.3 (3.4)

25.8 (4.1)

0.028*

Maximum extension (°)

4.6 (3.4)

3.5 (4.3)

0.159

Maximum flexion (°)

131.0 (6.8)

131.4 (6.7)

0.963

Knee society functional score

54.1 (13.3)

58.2 (14.7)

0.135

Femorotibial angle (°) in X-ray

182.9 (3.8)

182.3 (4.3)

0.426

KOOS (knees)

40

52

 Pain

52.2 (15.1)

47.8 (15.5)

0.185

 Symptom

59.6 (19.4)

57.9 (17.8)

0.666

 ADL

60.0 (13.0)

59.4 (16.4)

0.837

 Sports

22.7 (17.4)

22.6 (17.9)

0.981

 QOL

27.1(15.6)

29.5 (15.8)

0.477