ObjectiveOf the present study was to evaluate the impact of end-stage knee OA on patient’s perception of their functional abilities and quality of life (QoL) using the self-reported questionnaire; the Knee Injury and Osteoarthritis Outcome Score (KOOS), and to determine the contribution of knee pain on patient’s perceived outcomes.MethodsPatients with end-stage knee OA who are on the waiting list for total knee arthroplasty were recruited in this cross-sectional study. Patients were asked to fill out the KOOS questionnaire. Knee pain for both sides was quantified on a continuous scale from 0–10. Age, and anthropometric data were recorded. Descriptive statistics were calculated for patients’ characteristics, and for the scores of each KOOS subscale. Hierarchical linear regression models were created to determine the contributions of knee pain on two KOOS subscales; the function in daily living (KOOS-ADL), and the knee-related quality of life (KOOS-QoL).ResultsPatients in this study scored low across KOOS subscales (27.7% - 54.2%) with the QoL subscale being the lowest. After accounting for age and BMI, hierarchical linear regressions revealed that knee pain in both sides were determinants of self-perceived KOOS-ADLs, while only knee pain in the most-affected side significantly contributed to lower KOOS-QOL scores.ConclusionEnd-stage knee OA negatively impact the patients’ perceived function and quality of life. Patients’ KOOS scores were similar to those reported in other countries, with QoL being the domain most affected. Our findings demonstrate that the level of knee pain has a determinant effect on our patients’ perceptions of functional abilities and QoL. As waiting-list patients, addressing knee pain with a targeted regimen prior to TKA, as well as increasing patient’s awareness about knee pain management, may improve/ or minimize deterioration in perceived functional ability and QoL while awaiting TKA.