Comparison of KOOS Scores of Middle-Aged Patients Undergoing Total Knee Arthroplasty to the General Dutch Population Using KOOS Percentile Curves: The LOAS Study

BackgroundWe aimed to investigate the application of Knee Injury and Osteoarthritis Outcome Score (KOOS) percentile curves, using preoperative postoperative data patients with knee osteoarthritis undergoing total arthroplasty (TKA).MethodsWe used Longitudinal Leiden Orthopedics Outcomes Osteo-Arthritis study between 45 65 years primary TKA. KOOS scores (0-100) were obtained preoperatively 6, 12, 24 months after Preoperative radiographs assessed according Kellgren-Lawrence (KL) in a subset (37%) patients. Comorbidities self-reported standardized questionnaire. The median (interquartile range) population-level plotted on previously developed population-based curves. In addition, we curves patient level investigated differences KL ≤2 ≥3 presence (vs absence) comorbidities.ResultsThe population consisted 853 (62% women, mean age 59 years, body mass index 30 kg/m2) Preoperatively, all subscales at or below 2.5th percentile. Scores increased approximately 25th 12 postoperatively. Greater improvements observed pain less sport recreational function quality life. Patients higher without comorbidities showed greater improvements.ConclusionThe provided visual insights complaints relative general population. Furthermore, give insight how characteristics are correlated results.