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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