Abstract
BACKGROUND: Frailty heightens the risk of adverse perioperative outcomes in older patients with knee osteoarthritis (KOA), yet no Simplified Chinese version of the nine‑point Clinical Frailty Scale (CFS) has been validated for mainland China. This study translated and adapted the CFS into Simplified Chinese (SC‑CFS) and assessed its internal consistency, test-retest reliability, and construct validity in KOA patients awaiting total knee arthroplasty. METHODS: Following Brislin's forward-backward translation protocol, 253 KOA patients (mean age 75.4 ± 8.0 years; 75.9% female) completed the SC‑CFS preoperatively. Internal consistency was evaluated using Cronbach's α. A subsample of 60 patients completed the SC‑CFS twice, one week apart, before surgery to calculate the intraclass correlation coefficient (ICC) and standard error of measurement (SEM). Construct validity was examined via Spearman's correlations between SC‑CFS and the FRAIL scale, Barthel Index, and EQ‑5D‑5 L total score. Multivariate linear regression (adjusting for gender, education, living status, and chronic diseases) was used to test SC‑CFS's independent predictive validity on Barthel Index. RESULTS: The SC‑CFS demonstrated robust internal consistency (α = 0.91) and excellent test-retest reliability (ICC = 0.966; 95% CI 0.944-0.980; SEM = 0.30). Construct validity was confirmed by a strong positive correlation with the FRAIL scale (ρ = 0.802; 95% CI 0.752-0.843; p < 0.001), a moderate negative correlation with the Barthel Index (ρ = - 0.529; 95% CI - 0.615 to - 0.431; p < 0.001), and a weak positive correlation with EQ‑5D‑5 L (ρ = 0.260; 95% CI 0.138-0.375; p < 0.001). Multivariate regression identified SC‑CFS as the only independent predictor of Barthel Index (B = - 7.08 per CFS‑point, p < 0.001; adjusted R² = 0.30). CONCLUSION: The SC‑CFS is a reliable and valid instrument for preoperative frailty assessment in older Chinese KOA patients. Its robust psychometric properties support its integration into surgical risk stratification and personalized perioperative care.