Table 1 Preoperative and perioperative characteristics of the UKA patients

Age in years, mean (SD) [range]

65.0 (117) [48.0–76.0]

69.4 (11.1) [42.0–86.0]

  0.164

61.6 (12.3) [48.0–76.0]

64.6 (14.1) [42.0–83.0]

  0.490

Gender

 Male (%)

15 (83.3)

21 (26.9)

 < 0.001

5 (71.4)

15 (71.4)

  1.000

 Female (%)

3 (16.7)

57.00 (73.1)

2 (28.6)

6 (28.6)

Side

 Right (%)

12 (66.7)

36 (46.2)

  0.19

4 (57.1)

12 (57.1)

  1.000

 Left (%)

6 (33.3)

42 (53.8)

3 (42.9)

9 (42.9)

Localization of osteoarthritis:

 Medial (%)

18 (100)

72 (92.3)

  0.59

7 (100)

18 (85.7)

  0.551

 Lateral (%)

0 (0)

6 (7.7)

0 (0)

3 (14.3)

BMI (kg/m²), mean (SD) [range]

26.8 (2.3) [23.0–29.0]

28.2 (4.1) [21.0–38.4]

  0.555

27.4 (2.2) [23.0–29.0]

26.9 (2.8) [22.3–31.4]

  0.490

Smoking status:

 Never (%)

9 (50)

54 (69.2)

  0.001

4 (57.1)

9 (42.9)

  0.394

 Current smoker (%)

9 (50)

9 (11.6)

3 (42.9)

6 (28.6)

 Former (%)

0 (0)

15 (19.2)

0 (0)

6 (28.6)

Alcohol

 Never (%)

3 (16.767)

30 (38.5)

  0.129

1 (14.3)

6 (28.6)

  0.709

 With meals (%)

12 (66.7)

42 (53.8)

4 (57.1)

12 (57.1)

 During the day (%)

3 (16.7)

6 (7.7)

2 (28.6)

3 (14.3)

ASA class (%)

 ASA 1

6 (33.3)

16 (20.6)

  0.088

3 (42.9)

6 (28.6)

  0.394

 ASA 2

12 (66.7)

48 (61.5)

4 (57.1)

9 (42.9)

 ASA 3

0

14 (17.9)

0

6 (28.6)

Allergies

 Yes (%)

3 (16.7)

12 (15.4)

  1.000

0 (0)

3 (14.3)

  0.551

 No (%)

15 (83.3)

66 (84.6)

7 (100)

18 (85.7)

Operation time (min), mean (SD) [range]

45.0 (4.2) [40.0–50.0]

48.3 (16.2) [25.0–100.0]

  0.803

45.7 (4.5) [40.0–50.0]

55.0 (15.0) [35.0–75.0]

  0.184

Drain

 Yes (%)

0 (0)

6 (7.7)

  0.59

0 (0)

3 (14.3)

  0.551

 No (%)

18 (100)

72 (92.3)

7 (100)

18 (85.7)

Length of hospital stay (days), mean (SD) [range]

3.17 (0.4) [3.0–4.0]

13.2 (1.8) [10.0–16.0]

 < 0.001

3.3 (0.5) [3.0–4.0]

13.0 (1.9) [10.0–15.0]

 < 0.001