Table 2.
Demographic, clinical, symptom, and psychological characteristics of patients (N =156) prior to surgery
| 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 |
aAll opioids were converted to intravenous morphine equivalents. Value is the average dose of opioids over 4 days
bSingle item scores from the Brief Illness Perception Questionnaire