Depression Is Not Independently Associated with a Clinically Worse Functional Improvement but Associated with a Lower Reported Satisfaction Rate after Total Knee Arthroplasty

The aim of this study was to assess whether depression had a clinically significant influence on the functional improvement of total knee arthroplasty (TKA) according to the Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) score, and whether it influences patient satisfaction at 1 year. A retrospective cohort of 3,510 primary TKA was identified from an arthroplasty database. Patient demographics, comorbidities, WOMAC, and Short Form-12 (SF-12) scores were collected preoperatively and 1 year postoperatively. Patient satisfaction (overall, pain relief, return to work, and recreational activity) was assessed at 1 year. There were 444 (12.6%) patients who self-reported depression. Patients with depression were younger ( p <0.001), had a higher body mass index (BMI; p <0.001), were more likely to be female ( p <0.001), had lung ( p <0.001), neurological ( p =0.018), kidney ( p =0.001), liver ( p <0.001), and gastric ( p <0.001) disease, report associated diabetes ( p =0.001), and back pain ( p <0.001) relative to the subgroup without depression. All preoperative WOMAC functional measures were significantly ( p <0.001) worse in patients with reported depression. When adjusting for these confounding differences, patients with depression had a clinically equal improvement in their WOMAC scores at 1 year compared to those patients without. Depression was not associated with a clinically significant difference in improvement of knee-specific outcome (WOMAC) but was independently associated with a lower rate of patient satisfaction 1 year after TKA. Patients with depression were approximately twice as likely to be dissatisfied at 1 year when compared with those without depression. This is a prognostic retrospective cohort study and reflects level of evidence III.