Table 3 Demographics and comorbidities for patients undergoing primary total knee arthroplasty

Age (years) mean ± SD

65.9 ± 9.5

68.2 ± 9.0

 < 0.001

Sex

 < 0.001

 Female

14,309

8.1%

16,015

10.3%

BMI (kg/m²)

 < 0.001

  < 18

181

0.1%

221

0.1%

 18–25

14,309

8.1%

16.015

10.3%

 25–30

47,112

26.7%

41,306

26.5%

 30–35

52,210

29.8%

44,598

28.6%

 35–40

25,971

20.4%

30,836

19.8%

  > 40

26,289

14.9%

23,137

14.8%

Functional status prior to surgery

0.528

 Independent

174,574

99.9%

154,487

99.0%

 Dependent

1798

1.0%

1626

1.0%

ASA

 < 0.001

 1

3030

1.7%

2547

1.6%

 2

82,401

46.7%

76,620

49.1%

 3

87,695

49.7%

74,604

47.8%

  ≥ 4

3246

1.8%

2342

1.5%

Diabetes mellitus

0.032

 No diabetes mellitus

143,737

81.5%

127,171

81.5%

 Non-insulin-dependent diabetes mellitus

24,634

14.0%

22,107

14.0%

 Insulin-dependent diabetes mellitus

8001

4.5%

6835

4.4%

Smoker

 < 0.001

 No

158,498

89.9%

147,051

94.2%

 Yes

17,874

10.1%

9062

5.8%

Congestive heart failure

0.707

 No

175,794

99.7%

155,613

99.7%

 Yes

578

0.3%

500

0.3%