Predictive factors of length of hospital stay after primary total knee arthroplasty

To reduce post-operative length of hospital stay (PLOS) after primary total knee arthroplasty (TKA), the fast-track method was introduced which focusses on mobilising the patient within 2 h after surgery. The aim of this prospective study was to identify the factors that predict PLOS using the fast-track method. In a consecutive series from July 2012 to November 2012, all patients who were admitted for a primary TKA (Genesis II prosthesis, Smith and Nephew, Memphis, TN) were included in a prospective study. Demographic and relevant preoperative, perioperative and post-operative parameters for PLOS were collected. Multivariate linear regression analysis was performed to identify predictive factors. In total, 240 patients were included (59.6 % female) with a median age of 64.1 years (range 38-90). Median PLOS was 5 days (range 3-19). The predictive model suggested that ASA score (American Society of Anesthesiologists' physical status classification) wound exudate and range of motion (ROM) at the day of surgery (day 0) were significant predictive factors for PLOS using the fast-track procedure after TKA (adjusted R (2) = 0.43). Predictive factors for PLOS after TKA were ASA score, wound exudate and ROM at day 0. Adjustments in patient counselling, nursing ward, mode of physiotherapist training and discharge criteria regarding wound exudate may result in a further reduction of post-operative length of hospital stay. Prognostic studies: high-quality prospective cohort study, Level I.