Reasons and risk factors for ninety day re-admission following primary total knee arthroplasty in a high-volume centre

Purpose We aimed to assess the rates, reasons, and risk factors for 90-day re-admissions after total knee arthroplasty (TKA) in a European healthcare setting. Methods We identified all primary elective TKA procedures performed in 2015 at a single high-volume centre. Patients with unplanned re-admissions within 90 days of primary discharge were compared to a 1:4 control cohort of patients having no relevant re-admission. We calculated re-admission rates, recorded the reasons for re-admission, and identified independent predictors of re-admission. Results The 30-day and 90-day unplanned re-admission rates were 6.5% and 8.0%, respectively. The most common reason for re-admission within 90 days was infection (29.6%), followed by knee pain (14.1%), gastrointestinal complications (8.5%), and haematoma (8.5%). Multivariable logistic regression analysis revealed that the following factors were significant independent predictors of re-admission: asthma, psychiatric disease, pre-operative tibiofemoral valgus angle, and pre-operative knee flexion deficit. Conclusions The re-admission rates in our health-care setting were slightly higher than those previously reported. Independent risk factors for re-admissions included pre-operative mechanical axis, range of motion, asthma, and psychiatric disease. Our present results will facilitate the targeting of new subgroups of TKA patients when developing new interventions to further reduce the total re-admission risk after TKA.Peer reviewe