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Table 1 Predictors of change in the OKS between 6 and 12 months after TKA

From: One-year Oxford knee scores should be used in preference to 6-month scores when assessing the outcome of total knee arthroplasty

Demographic

Descriptive

Number

Mean (SD)

Difference/ correlation

95% CI

P value*

Gender

Male

711

1.1 (6.3)

Diff = 0.0

−0.6 to 0.6

0.98

Female

863

1.1 (5.6)

   

Age

  

r = −0.04

 

0.16**

BMI

  

r = −0.05

 

0.054**

Comorbidity

Not present

  

Reference***

  

MI

65

0.3 (7.4)

Diff = 0.8

−0.6 to 2.3

0.27

Heart Failure

15

3.1 (9.6)

Diff = 2.0

−1.0 to 5.0

0.18

PVD

31

1.1 (8.1)

Diff = 0.1

−2.0 to 2.2

0.93

Stroke

10

−1.8 (8.1)

Diff = 3.0

−0.7 to 6.6

0.11

COPD

57

0.8 (6.6)

Diff = 0.4

−1.2 to 1.9

0.66

Diabetes

189

0.3 (6.6)

Diff = −1.0

−1.9 to −0.1

0.04

Back pain

590

1.2 (6.4)

Diff = 0.2

−0.5 to 0.8

0.62

Joint pain

1041

1.0 (5.9)

Diff = 0.4

−0.3 to 1.1

0.22

Functional measures

OKS

Preoperative

1574

r = 0.08

 

0.002**

6 months

1574

r = −0.23

 

< 0.001**

EQ 5D

Preoperative

1570

r = 0.04

 

0.14**

6 months

1567

r = −0.11

 

< 0.001**

  1. TKA total knee arthroplasty, OKS Oxford Knee Score, EQ 5D EuroQoL 5-Dimension questionnaire, BMI body mass index; MI myocardial infarction, PVD peripheral vascular disease, COPD chronic obstructive pulmonary disorder, CI confidence interval, Diff difference
  2. *Unpaired t test unless otherwise stated. **Pearson correlation. ***Difference relative to a patient without the stated comorbidity
  3. Bold indicates statistical significance