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Table 4 Baseline characteristics of patients undergoing primary THA for continuous variables

From: Important patient characteristics differ prior to total knee arthroplasty and total hip arthroplasty between Switzerland and the United States

 

Geneva registry Switzerland (N = 1,023)

FORCE-TJR United States (N = 4,647)

Mean difference (95% CI)

P-value****

Age at operation, mean [±SD]

68.2 [±12.9]

64.6 [±10.7]

3.6 (2.8; 4.3)

0.000

Preoperative BMI, mean [±SD]*

26.87 [±5.0]

29.12 [±5.7]

-2.2 (-1.9; -2.6)

0.000

Mean age in each BMI category, [±SD]

    

 <25

68.61 [±14.7]

66.35 [±11.5]

2.3 (3.7; 0.8)

0.000

 25–29.9

68.55 [±12.2]

65.42 [±10.4]

3.1 (1.9; 4.3)

0.000

 30–34.9

67.24 [±11.0]

63.82 [±10.1]

3.4 (1.8; 5.1)

0.000

 ≥35

65.68 [±8.8]

61.17 [±9.8]

4.5 (2.1; 7.0)

0.000

Preoperative scores, mean [±SD]

  

Mean difference

 

(95% CI)/Effect size

 

 WOMAC pain

39.51 [±18.5]

47.81 [±19.8]

-8.3 (-9.8; -6.8)/0.43

0.000

 WOMAC function

40.21 [±19.5]

44.24 [±19.2]

-4.0 (-5.6; -2.5)/0.21

0.000

 SF-12 Physical Component Summary

33.39 [±7.9]

31.26 [±8.5]

2.1 (1.5; 2.8)/0.26

0.000

 SF-12 Mental Component Summary

43.91 [+11.7]

49.97 [±12.6]

-6.1 (-7.0; -5.1)/0.5

0.000

  1. *BMI was available for 6,452 TKAs (96.6%) from FORCE-TJR
  2. **In the Geneva cohort information on education was routinely collected only since 2012
  3. ***FORCE-TJR collects RA versus OA
  4. ****Pearson chi2 tests were used for categorical variables, and two-sample Wilcoxon rank-sum (Mann-Whitney) tests were used for continuous variables