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Table 2 Baseline characteristics of patients undergoing primary TKA 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 = 823)

FORCE-TJR United States (N = 6,680)

Mean difference (95% CI)

P-value****

Age at operation, mean [±SD]

72.3 [±9.4]

66.7 [±9.4]

5.6 (4.9; 6.3)

0.000

Preoperative BMI, mean [±SD]*

29.6 [±5.9]

31.53 [±6.2]

-1.9 (-1.5; -2.4)

0.000

Mean age in each BMI category, [±SD]

    

 <25

72.9 [±10.9]

69.38 [±10.2]

3.5 (1.8; 5.2)

0.000

 25–29.9

74.25 [±8.6]

68.51 [±9.4]

5.8 (4.6; 6.9)

0.000

 30–34.9

71.02 [±8.8]

66.64 [±8.7]

4.4 (3.1; 5.6)

0.000

 ≥35

69.16 [±8.7]

63.29 [±8.5]

5.9 (4.4; 7.3)

0.000

Preoperative scores, mean [±SD]

  

Mean difference

 

(95% CI)/Effect size

 

 WOMAC pain

41.0 [±17.9]

51.59 [±19.0]

-10.6 (-12.2; -9.1)/0.57

0.000

 WOMAC function

44.82 [±19.2]

52.09 [±18.6]

-7.3 (-8.9; -5.7)/0.39

0.000

 SF-12 Physical Component Summary

34.45 [±7.6]

32.68 [±8.3]

1.8 (1.1; -2.5)/0.23

0.000

 SF-12 Mental Component Summary

44.84 [±11.2]

51.40 [±12.3]

-6.6 (-7.6; -5.5)/0.56

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