High levels of preoperative pain and fatigue are red flags for moderate‐severe pain 12 months after total knee arthroplasty—A longitudinal cohort study

BACKGROUND: Moderate/severe pain after total knee arthroplasty (TKA) is a poor surgical outcome. Many studies have identified preoperative risk factors of pain after TKA, but studies of the joint contributions of co‐occurring symptoms are lacking. METHODS: Patients undergoing primary TKA (n = 202) were enrolled in a longitudinal cohort study. Preoperatively, patients completed questionnaires measuring demographics and symptoms (pain, fatigue, sleep problems and depression). Pain was re‐assessed 12 months after TKA. Logistic regression analysis was used to compute the probabilities of moderate‐severe pain at 12 months based on preoperative symptom levels, and results were combined into a risk matrix. RESULTS: More than one‐third (40%) of patients (n = 187) reported moderate‐severe pain after TKA. Among preoperative risk factors included in the logistic regression analyses were age, sex, pain, fatigue, sleep problems and depression. Adjusting for possible confounders, fatigue (p = 0.02) and pain (p = 0.01) were significant risk factors for moderate‐severe pain at 12‐months follow‐up and were retained in the final risk matrix. The co‐occurrence of high‐preoperative fatigue and pain scores resulted in 57% estimated probability of moderate‐severe pain at 12 months. Similarly, the co‐occurrence of low‐preoperative fatigue and pain scores resulted in 14% estimated probability of moderate‐severe pain 12 months after TKA. CONCLUSION: The combination of high fatigue and pain scores prior to surgery was a key risk factor for moderate‐severe pain 12 months after TKA. Mapping of these factors could be used preoperatively to identify patients who are at risk to experience a poor outcome of TKA.