ICF rehabilitation set responsiveness after total knee arthroplasty: a retrospective study

The International Classification of Functioning, Disability and Health-Rehabilitation Set (ICF-RS) is a standardized tool for multidimensional rehabilitation assessment, but its responsiveness in post-total knee arthroplasty (TKA) inpatient settings remains underexplored.

A retrospective single-center cohort study was conducted on 47 patients who underwent primary unilateral TKA and received inpatient rehabilitation in Changsha, China (January 2023-December 2024). ICF-RS scores (30 categories) were assessed at admission and discharge. Responsiveness was evaluated using Wilcoxon signed-rank tests with Benjamini-Hochberg FDR correction. Response counts (improved/stable/worsened) were the primary outcome presentation.

Of 30 ICF-RS categories, 27 showed 100% data completeness; 3 social/sexual items had substantial missingness. Following rehabilitation, 23 categories demonstrated statistically significant improvement after FDR correction. Consistent directional improvement was observed in mobility (d450 Walking: 24/47 improved), self-care (d510-d540), and pain (b280: 26/47 improved) domains. The total score decreased from 47.51 ± 13.59 to 35.81 ± 11.38 (Cohen's d = 1.51). Notably, b710 (joint mobility) showed no responsiveness (0/47 improved, 1/47 worsened), despite expected clinical range-of-motion gains.

ICF-RS demonstrates responsiveness to post-TKA inpatient rehabilitation for most functional domains. The lack of change in b710 highlights a limitation of generic assessment tools for capturing localized physical impairments in single-joint conditions, suggesting the need for complementary condition-specific measures. The study context-where ICF-RS scores influence reimbursement-underscores the importance of assessment integrity considerations in function-based payment implementations.