Perceived stress, cortisol predict recovery from arthroscopic knee surgery

Effects of perceived stress and basal cortisol levels on surgical recovery were examined. Participants (n = 57) undergoing elective arthroscopic meniscus surgery provided salivary cortisol samples one week prior to surgery, and completed the Perceived Stress Scale (PSS), the Pain Severity and Interference from Pain subscales of the West Haven-Yale Multidimensional Pain inventory, and the Lysholm Knee Scoring Scale at baseline and at one, three, and eight weeks following surgery. Linear mixed model analyses were used to assess the impact of perceived stress and cortisol on the recovery measures. Gender, age, and body mass index (BMI) were included in the analysis to account for pertinent demographic and clinical variables. Results indicated that PSS scores during recovery significantly predicted postoperative pain symptoms: individuals scoring one mean point higher on the PSS tended to report 16.5% more pain than the average pain report across time. A trend was found for the relationship between PSS scores and knee function, corresponding with a 4.7% average decrease in knee function scores for each additional mean PSS score. Baseline evening cortisol levels significantly predicted knee function and pain scores following surgery. One log nmol/L increase in basal bedtime salivary cortisol was associated to a 6.0% decrease in knee function scores and 15.5% increase in pain report across time. Women tended to report significantly more pain and worse knee function; however, after controlling for baseline knee function and pain, the effect for gender was no longer significant. No effects were found for age or BMI on surgical outcome. The results of this study indicate that higher levels of perceived stress, both prior to surgery and during the recovery period, were associated with worse postoperative recovery. Elevated basal evening cortisol predicted poorer postoperative functional recovery and increased pain symptoms through eight weeks following surgery. Furthermore, perceived stress and evening cortisol levels appear to be unique predictors of surgical recovery.