Background: The number of Parkinson's patients (PD) undergoing total knee arthroplasty (TKA) is increasing. The purpose of the study was to characterize quality of life (QOL) outcomes for patients with coexisting PD and knee osteoarthritis (KOA) following TKA.Methods: Patients with coexisting PD and KOA undergoing TKA between June 2014 and June 2020 were included. These patients were matched to controls with KOA alone by age, gender, basic social background information and Knee society score(KSS). The primary measure was to assess the QOL by the absolute changes in the EuroQOL5-Dimensions (EQ-5D), Pain and Disability Questionnaire (PDQ), and Patient Health Questionnaire-9(PHQ-9) at the last follow-up (LFU). Secondary measures were changes in QOL that exceeded the minimum clinically important difference value (MCID). Data on the health status and QOL of all patients were collected. Simple and multivariate regression analysis was used to evaluate the impact of PD on their QOL.Results: Twelve KOA patients with PD were compared with 48 controls. Control patients experienced QOL improvement across all three measures:EQ-5D index (0.545-0.717, P <0.01), PDQ (81.1-52.3, P < 0.01) and PHQ-9(8.22-5.91, P < 0.01) were significantly improved at the LFU; while in patients with PD, only PDQ (91.0-81.4, P =0.03) slightly improved. There were significant differences in the improvement of QOL between PD patients and the control group through EQ-5D (0.531 vs.0.717, P< 0.01) and PDQ (81.4vs.52.3, P <0.01) at the LFU.Conclusion: TKA has no benefit of QOL beyond a slight improvement in pain-related disability in the KOA patients with PD.