Prediction of Pain and Opioid Utilization in the Perioperative Period in Patients Undergoing Primary Knee Arthroplasty: Psychophysical and Psychosocial Factors.

Objective To identify factors associated with pain severity and opioid consumption in the early perioperative period. Design Prospective observational cohort study. Setting Tertiary academic medical center. Subjects Patients with osteoarthritis older than age 45 years undergoing primary total knee replacement at Brigham and Women's Hospital. A total of 126 patients enrolled. Methods Preoperatively, pain questionnaires and quantitative sensory testing were performed on patients to develop a psychosocial and psychophysical profile. Postoperatively, pain scores and opioid consumption were measured as primary end points. Univariate and multiple linear regression analyses were performed to determine the predictive value of these characteristics on perioperative pain scores and opioid consumption. Results Regression analysis revealed several predictors of acute postoperative pain scores including temporal summation of pain (TSP; P  = 0.001), body mass index (BMI; P  = 0.044), number of previous knee surgeries (P  = 0.006), and female gender (P  = 0.023). Similarly, predictors of opioid utilization included TSP (P  = 0.011), BMI (P  = 0.02), age (P  = <0.001), and tourniquet time (P  = 0.003). Conclusions The only significant, unique predictors of both pain and opioid consumption were TSP, an index of central pain facilitatory processes, and BMI. Interestingly, psychosocial factors, such as catastrophizing and somatization, although correlated with postoperative pain scores and opioid consumption, generally did not independently explain substantial variance in these measures. This study suggests that BMI and quantitative sensory testing, specifically the temporal summation of pain, may provide value in the preoperative assessment of patients undergoing total knee arthroplasty and other surgeries via predicting their level of risk for adverse pain outcomes. [ABSTRACT FROM AUTHOR]

Copyright of Pain Medicine is the property of Oxford University Press / USA and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)