Preoperative depressive symptoms have been shown in some but not all studies to be associated with poor self-reported pain and function outcomes. In addition, depressive symptoms after surgery have been shown to improve relative to preoperative levels.
We hypothesized that (1) preoperative depressive symptoms would predict postoperative pain; (2) depressive symptoms would decrease after surgery; and (3) preoperative depressive symptoms would increase as the scheduled surgery date approached.
Data from the Osteoarthritis Initiative, a National Institutes of Health-funded prospective multiyear cohort study, were used in this retrospective analysis. Persons from four communities were eligible if they had radiographic knee osteoarthritis or were at risk for developing knee osteoarthritis based on occupational, medical history, or body weight risk factors. A total of 4796 persons participated and rates of followup were 80% or greater over the course of the study. Participants completed a validated depressive symptom scale and the Knee Injury and Osteoarthritis Outcome Scale pain scale each year for 3 years before and 3 years after TKA. Latent growth curve modeling was used to model intercepts and slopes of pre- and postoperative depression and pain. Preoperative trajectories and intercepts were then used to predict postoperative pain and depressive symptoms adjusting for confounding variables.
After adjustment for potential confounding, we found no evidence that preoperative depressive symptoms predicted postoperative pain with function (estimate, 0.1; 95% confidence interval, -0.31 to 0.50; p = 0.64) or that depressive symptoms were reduced after surgery (z = 0.06, p = 0.80). We also found no evidence to indicate that preoperative depressive symptoms increased as the date of surgery approached (linear slope = 0.28, SE = 0.19, p = 0.15).
Level I, prognostic study.
Preoperative and postoperative depressive symptoms in patients before and after TKA did not appreciably change over a 6-year perioperative period. Patient depressive symptoms were not reduced after surgery and did not appear to be related to less pain postoperatively. Our findings of no association between preoperative depressive symptom severity and postoperative pain and no reduction in postoperative depressive symptoms run counter to other available evidence, potentially attributable, in part, to a data collection process that occurred outside of orthopaedic surgeons' offices. Future research is needed to more fully explore the potential role of social desirability, the concept that patients respond in a way that they think the researcher or clinician wants them to respond in lieu of responding in a way that truly reflects the patient's status. Social desirability may influence a TKA patient's pain and function outcome assessment.