Objective functional performance 1 year after total knee arthroplasty does not differ for patients with symptoms of anxiety, depression or pain catastrophizing: A prospective study of 289 patients

Purpose: Preoperative anxiety, depression and pain catastrophizing (PC) symptoms are associated with inferior patient-reported outcomes after total knee arthroplasty (TKA). It remains unclear whether such differences also exist for objective outcomes such as strength, range of motion (ROM) and timed up and go (TUG). This study aimed to investigate whether objective functional performance differs up to 12 months postoperatively in patients with these psychological symptoms. 

Methods: A prospective cohort of 289 TKA patients was analysed (55% female, age 71 [65–76]). Anxiety (21%), depression (17%) and PC (14%) were assessed preoperatively using the Hospital Anxiety and Depression Scale and Pain Catastrophizing Scale. Objective outcomes consisting of maximum strength (strength), strength endurance (SE), ROM and TUG were measured preoperatively and at 6 and 12 months postoperatively. Between-group comparisons were adjusted for confounders (age, sex, American Society of Anesthesiologists, body mass index, surgical approach, baseline functional performance) using multivariable regression. 

Results: Preoperatively, mainly anxiety- and depression-symptoms were associated with lower strength and SE (all p < 0.05), and TUG was worse in depression- and PC patients (all p (Formula presented.) 0.021). ROM did not differ between groups. At 6 and 12 months, unadjusted analyses showed continued associations between anxiety/depression and inferior flexion strength or SE (all p (Formula presented.) 0.023), but these either resolved by 12 months (p = 0.843) or lost significance after multivariable adjustment (p (Formula presented.) 0.052), except for flexion strength in anxiety patients (p = 0.033). PC symptoms were associated with greater TUG improvement at 12 months (p = 0.005), though minimal clinically important difference attainment and ROM outcomes remained similar across groups. 

Conclusion: Although preoperative psychological symptoms are associated with poorer objective outcomes, these differences resolve by 6–12 months postoperative follow-up. After 1 year, similar objective outcomes are attained for patients with symptoms of anxiety, depression or PC. Interpreting this in the bigger scope, the importance of integrating psychological support into the perioperative pathway to align subjective and objective outcomes is underlined. 

Level of Evidence: Level II, prognostic cohort study.