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Table 2 Demographic, clinical, symptom, and psychological characteristics of patients (N =156) prior to surgery

From: The relationship between pain with walking and self-rated health 12 months following total knee arthroplasty: a longitudinal study

Demographic characteristics   Mean SD
 Age Years 68.9 9.1
   n %
 Sex Female 106 67.9
 Cohabitation status Married/partnered 95 60.9
 Employment status Unemployed/retired 100 64.1
 Education level College/university 76 48.7
Clinical characteristics   Mean SD
  Body mass index (BMI) 29.2 4.6
  n %
Obese (BMI ≥30 kg/m2) 61 39.1
Morbidly obese (BMI ≥40 kg/m2) 4 2.6
  Mean SD
Number of comorbidities (0–5) 1.2 1.0
American Society of Anesthesiologists’ physical status classification score 2.0 0.5
Systolic blood pressure 138.6 16.1
C-reactive protein 3.3 3.0
Creatinine 77.6 23.0
Pain characteristics    
  Average pain prior to surgery (0–10) 5.3 1.8
Worst pain prior to surgery (0–10) 5.5 2.1
Pain interference with function (0–10) 4.4 2.0
 Number of painful sites Prior to surgery 2.1 1.6
  12 months after surgery 2.0 1.2
  n %
Contralateral knee pain 12 months – yes (n = 130) 40 30.8
 Pain interference walking group    
  Recurrent interference group 36 23.1
Continuous improvement group 120 76.9
Perioperative characteristics:    
 Anesthesia Regional anesthesia 132 84.6
  Total intravenous anesthesia 24 15.4
  Mean SD
Length of surgery (minutes) 65 13.0
Length of stay (days) 4.6 1.1
 Pain management Average dose of opioids (mg)a 12.6 6.2
   n %
Ketamine - yes 22 14.1
Preoperative symptoms   Mean SD
  Fatigue severity (1–10) 2.6 2.2
Fatigue interference (1–7) 3.9 1.5
Depression (0–21) 3.4 3.1
Anxiety (0–21) 4.6 3.7
Psychological characteristicsb    
  Consequences (0–10) 6.2 1.8
Personal control (0–10) 5.4 2.3
Identity (0–10) 6.6 1.7
Concern (0–10) 5.1 2.6
Emotional response (0–10) 4.5 2.6
Health status    
  Preoperative self-rated health 60.9 19.7
Self-rated health, 12 months 74.7 16.0
  1. aAll opioids were converted to intravenous morphine equivalents. Value is the average dose of opioids over 4 days
  2. bSingle item scores from the Brief Illness Perception Questionnaire