The Effect of Depression on Patient-Reported Outcomes After Total Joint Arthroplasty Is Modulated by Baseline Mental Health: A Registry Study

Depression and poor mental health are known to be negative predictors of patient-reported outcomes after total joint arthroplasty. Although previous studies have examined these risk factors in isolation to each other, they are, in reality, closely related, and yet each represents a different aspect of one's psychological well-being. The objective of this study was to investigate the association between depression and patient-reported outcomes, taking into account patients' baseline mental health. Our prospective, institutional joint registry was queried for patients who had undergone primary elective total joint arthroplasty and had a minimum follow-up of 1 year. Baseline mental health was measured by the Short Form-12 Mental Component Summary (SF-12 MCS). Four cohorts were analyzed on the basis of the presence or absence of depression and patients' SF-12 MCS scores at the time of the surgical procedure, which were categorized as either poor or good on the basis of previously defined cutoffs. The primary outcomes were the net changes in SF-12 MCS, SF-12 Physical Component Summary (PCS), and Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) scores at 4 and 12 months postoperatively. Univariate and mixed-effects model analyses were performed to control for potential confounding factors. Patients with depression but good baseline mental health achieved gains in patient-reported outcomes that were comparable with those of normal controls (p > 0.05). Patients with poor baseline mental health achieved significant gains in all patient-reported outcomes, but the changes were largest for those without depression (p < 0.05). Only patients with depression and poor baseline mental health did not cross the threshold for good mental health at the time of the latest follow-up despite achieving similar gains in physical function compared with their counterparts who did not have depression. The effect of depression on patient-reported outcomes is more complex but less pessimistic than previously thought. Patients with depression undergoing total joint arthroplasty may have significant improvements in their patient-reported outcomes, but the net gains are modulated by their mental health at the time of the surgical procedure. Preoperative screening of patients with depression using the SF-12 MCS may help to identify those who are at risk for attaining suboptimal patient-reported outcomes and may benefit from counseling or psychiatric referral for optimi