UCSF

This study explores sociodemographic, clinical, and surgical factors in relation to pain trajectories during the first 3 days following total knee arthroplasty (TKA). 100 patients (mean age 63.5 ± 7.8 years and 93% female) consecutively admitted for uncomplicated primary TKA were prospectively included. Postoperative pain was assessed using pain diaries. Measures of preoperative pain, symptoms, daily functioning, quality of life, comorbidities, knee function, perioperative characteristics, and physical/biochemical parameters were also evaluated. All pain ratings decreased in the three days following surgery (p < .001) as well as the reported number of daily hours in moderate/severe pain (p < .001). Women reported more pain than men (p = .009). Pain trajectories did not differ by education, employment, cohabitation, or any patient clinical and biochemical characteristics but were significantly related to preoperative anxiety (p = .029). Patients reporting moderate/severe pain prior to surgery also reported more hours in moderate/severe pain on days 0-3 postoperatively (p = .029). Patients with surgeries longer than 90 min reported more hours of moderate/severe pain compared with patients who had shorter surgeries (p = .008), and similar results were observed for ratings of pain with activity (p = .012). In this sample, only female gender, higher levels of preoperative pain and anxiety, and longer surgical duration were associated with increased pain after TKA.