Epidemiological characteristics and influencing factors of rehabilitation length of stay among hospitalized patients after knee arthroplasty in Beijing, China: a retrospective study

Study design Retrospective epidemiological study. Objectives To analyze the epidemiological characteristics of patients receiving inpatient rehabilitation after knee arthroplasty, evaluate their rehabilitation LoS, and explore the factors influencing rehabilitation LoS. Methods This retrospective study consecutively enrolled patients receiving inpatient rehabilitation after primary total or unicompartmental knee arthroplasty at a tertiary rehabilitation hospital in Beijing from 2023 to 2026. Data on demographics, insurance type, comorbidities, length of stay, Modified Barthel Index and hospitalization costs were collected. Statistical analyses included the Mann–Whitney U test, Spearman's rank correlation analysis, and a Gamma generalized linear model to explore predictors of rehabilitation length of stay. Results Among all included admissions, there were 60 admissions (58.3%) covered by Beijing local medical insurance and 43 admissions (41.7%) with off-site medical insurance. The median length of rehabilitation stay was 25 days, and the median time to rehab admission from primary surgery to admission to the rehabilitation center was 5 days. The median total rehabilitation hospitalization cost was 28,337.1 Chinese Yuan (3,987.1 US dollars), among which rehabilitation training expenses accounted for 49.23%. After adjusting for confounding factors, only type of medical insurance was identified as an independent influencing factor of length of hospital stay ( P < 0.05). Conclusions This study implies that orthopedic hierarchical care and integrated rehabilitation models may help optimize rehabilitation length of stay and ease patients’ economic burden. Further investigation of cross-institutional rapid referral pathways is needed.