The effects of psychological factors on the short-term outcome after uncomplicated total knee arthroplasty (TKA) have been described in several studies. However, the effects of mental factors on the midterm (5-year) outcome have not been described in the literature. This study was performed to examine the influence of pain catastrophizing, anxiety, depression symptoms, and somatization dysfunction on the outcome of TKA during a 5-year follow-up.
One hundred fifty patients were enrolled in this prospective study. The following mental parameters were assessed in all patients: pain catastrophizing (Pain Catastrophizing Scale), anxiety (State-Trait Anxiety Inventory), depressive symptoms and somatization dysfunction (Patient Health Questionnaire). The primary outcome measure was postoperative pain on a numerical rating scale. The secondary outcome measures were the Knee Injury and Osteoarthritis Outcome Score and patient satisfaction. Intergroup differences were tested using an independent t-test. Odds ratios were calculated to determine the probability of an unsatisfactory outcome.
At the 5-year follow-up, only depressive symptoms and somatization dysfunction had a significant effect on postoperative pain (numerical rating scale score). This significant effect was also observed for the different Knee Injury and Osteoarthritis Outcome Score subscales and patient satisfaction (P = .010-.020). Pain catastrophizing and anxiety had only a small effect on the clinical outcome at 5 years postoperatively.
Level II, diagnostic study.
The effects of psychopathological factors (depressive symptoms and somatization dysfunction) on the clinical outcome after uncomplicated TKA persist for up to 5 years. Preoperative screening for and subsequent treatment of these psychological disorders may improve patient-reported outcomes after TKA.