Improvement in Quality of Life, Pain and Function After Total and Unicompartmental Knee Replacement: A Secondary Analysis of 12-Month Post-Operative Outcomes.

Objectives: To investigate variables associated with improvement in quality of life (QOL) after primary knee replacement. QOL outcomes between individuals undergoing total knee replacement (TKR) and unicompartmental knee replacement (UKR) were compared. Materials and Methods: Participants were adults (n = 497) undergoing TKR or UKR for osteoarthritis between January 2017 and October 2020 in a large publicly funded tertiary hospital in New Zealand. Participants completed patient-reported outcome measures of QOL, pain and function, preoperatively, 6 and 12 months postoperatively. Results: QOL improved pre- to postoperatively for both TKR and UKR groups, and the main QOL gains for both groups were evident in the first 6 months after joint replacement. Notably, QOL did not differ between groups at any assessment point (p > 0.05). Improvement in QOL was more correlated with improved pain and function than with person factors such as demographics and comorbidity burden (p < 0.01). Conclusions: This study adds to a growing literature showing that knee replacement contributes to substantial improvements in QOL outcomes. Future QOL outcome research in the knee replacement population should consider using more precise measures of function to better understand the impacts of these factors on QOL improvement.