Factors affecting the length of hospital stay for total knee arthroplasty in Japan: a retrospective study using the diagnosis procedure combination database

Background We aimed to evaluate the length of hospital stay following total knee arthroplasty to determine the impact of relevant factors using data from the Diagnosis Procedure Combination database. Methods This was a retrospective observational study. The study cohort included 5,831 patients who had osteoarthritis of the knee and had undergone total knee replacement between February 2018 and October 2022 at 38 hospitals. Results Multivariate analysis showed that the factors influencing the length of stay included: age (p < 0.001), height (p < 0.001), weight (p = 0.049), body mass index (p = 0.008), Barthel index (p < 0.001), method of anesthesia (p < 0.001), bone transplant (p = 0.010), timing of postoperative rehabilitation (p < 0.001), atrial fibrillation (p < 0.001), chronic pain (p < 0.001), and number of institutionally treated cases (p < 0.001) (r = 0.451, p < 0.001). Conclusions Shorter or longer hospital stays were found to be associated with the patients' background characteristics and facility-specific factors; these can lead to more accurate estimates of the length of hospital stay and appropriate allocation of resources.