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

Abstract

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

Digital Rehabilitation after Knee Arthroplasty: A Multi-Center Prospective Longitudinal Cohort Study

“…The results of our study demonstrated a significant improvement in the Oxford Knee Score, all KOOS sub-scores, and the KSS satisfaction sub-score at 6 months post-surgery. The significant improvements were similar to those previously reported after in-person interventions in Belgium and The Netherlands [32][33][34], and the population studied was representative of the registry in terms of demographics [35]. The absence of direct comparison with standard protocols in our study limits further conclusions, but the results of our study confirmed previous reports in the literature.…”

Preoperative Factors Affecting Patient-reported Outcome Measures for Total Knee Arthroplasty

“…Total joint arthroplasty reportedly improves HRQOL after surgery. 7,29) We observed that the preoperative KOOS scores in our study were similar to 30,31) or better than 32) those reported in previous studies. In studies with worse preoperative KOOS scores, the patients were younger (mean age, approximately 60 years) at the time of TKA.…”

“…The observed differences may be explained by differences in lifestyle and physical activities associated with age and anxiety about the future. In a large prospective cohort study, 32) the KOOS scores at 12 months post-TKA were similar to the re-sults of the current study. However, in that study, the KOOS scores at 24 months post-TKA remained unchanged from those at 12 months post-TKA.…”