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Table 1 Cohort description

From: Identifying individuals with chronic pain after knee replacement: a population-cohort, cluster-analysis of Oxford knee scores in 128,145 patients from the English National Health Service

Observations: n 126,064
Gender: n (%)
 Female 68,114 (54%)
 Male 49,306 (39%)
 Not specified 106 (0%)
 Missing 8538 (7%)
Age band: n (%)
 40–49 years of age 258 (0%)
 50–59 years of age 11,380 (9%)
 60–69 years of age 43,583 (35%)
 70–79 years of age 48,073 (38%)
 80–89 years of age 14,226 (11%)
 90+ years of age 6 (0%)
 Missing 8538 (7%)
Pre-op OKS score1
 Mean (SD) 19.0 (8)
 Median (IQR) 19 (11)
 Missing 1473 (1%)
Pre-op EQ-5D index2
 Mean (SD) 0.414(0.31)
 Median (IQR) 0.587 (0.603)
 Missing 7077 (6%)
Pre-op EQ-5D VAS3 “Your own health state today”
 Mean (SD) 68.2(20)
 Median (IQR) 70 (25)
 Missing 13,110 (10%)
“How would you describe the results of your operation?” n (%)
 Excellent 31,827 (25%)
 Very good 44,472 (35%)
 Good 30,670 (24%)
 Fair or Poor 18,355 (15%)
 Missing 740 (1%)
“Overall, how are your problems now, compared to before your operation?” n (%)
 Much better 92,164 (73%)
 A little better 20,276 (16%)
 About the same 5775 (5%)
 A little or much worse 7388 (6%)
 Missing 461 (0%)
Post-op OKS scorea
 Mean (SD) 35.2 (10)
 Median (IQR) 37 (14)
 Missing 46 (0%)
Post-op EQ-5D indexb
 Mean (SD) 0.734(0.25)
 Median(IQR) 0.760 (0.344)
 Missing 6084 (5%)
Post-op EQ-5D VASc “Your own health state today”
 Mean (SD) 73.8 (20)
 Median (IQR) 80 (25)
 Missing 6746 (5%)
  1. acaptures knee pain and function, scored from 0 to 48 where 0 indicates most and 48 least pain and functional limitations
  2. ba health-related quality of life measure where 0 represents death and 1 refers to perfect health
  3. ca Visual Analogue Scale ranging from 0 to 100, where 0 represents the worst and 100 the best imaginable health state