Incidence, patterns and risk factors for readmission following knee arthroplasty in China: A national retrospective cohort study

Background: Limited data exist on readmission following knee arthroplasty (KA) in countries without well -established referral or extended care systems. This study aimed to investigate the incidence, patterns and risk factors for readmission following KA in China.Material and methods: In this national retrospective cohort study, we reviewed 167,265 primary KAs registered in the Hospital Quality Monitoring System in China between 2013 and 2018. Readmissions after KA within 30 and 90 days were evaluated. The causes for readmission were identified and classified as surgical or medical. The potential risk factors of readmission were assessed using multivariable logistic regression.Results: 4017 (2.4%) patients readmitted within 30 days, and 7258 (4.3%) patients readmitted within 90 days. The readmission rate exhibited a downward trend during the period from 2013 to 2018 (2.7%-2.3% for 30-day readmission; 4.5%-4.2% for 90-day readmission). Surgical causes contributed to 54.3% readmissions within 30 days and 47.3% readmissions within 90 days. Wound infection/complication, joint pain, and thromboembolism were the most frequently reported reasons for surgical readmission. Older age, male sex, single marital status, non-osteoarthritis indication, a high comorbidity index, non-provincial hospitals, low hospital volume, and longer length of stay were associated with an increased risk of readmission. The geographic regions of hospitals contributed greatly to the variety of readmissions.Conclusion: The readmission rate following KA decreased from 2013 to 2018. Surgery-related causes, especially wound infection/complication and pain, accounted for a large proportion. Both patient and hospital factors were associated with readmissions. Improved primary care and targeted measures are needed to help further prevent readmissions and optimize resource utilization.