Patient-Controlled Analgesia and Peripheral Nerve Block Increase the Risk of Post-operative Urinary Retention after Total Knee Arthroplasty in Asian Patients.

Introduction: Post-operative urinary retention (POUR) is a common complication after total knee arthroplasty (TKA) and may result in severe complications such as urinary tract infection and deep joint sepsis, leading to prolonged hospital stay and increased medical costs. Hence a retrospective study was performed to identify the incidence and modifiable factors associated with POUR after elective TKA in Asian patients with the aim to prevent POUR and its undesirable consequences. Materials and Methods: The medical records of 496 consecutive patients who underwent elective TKA between 1 August 2017 and 30 July 2018 were reviewed. There were 154 male (31.0%) and 342 female (69.0%) patients with an average age of 68 years old. The incidence of POUR was analysed with respect to various modifiable and non-modifiable risk factors, including patient demographics, medical comorbidities, duration of surgery, type of intra-operative anaesthesia and post-operative analgesia and early initiation of physiotherapy using univariate and multivariate analyses. Results: A total of 120 (24.2%) of the 496 patients who underwent elective TKA developed POUR. The odds of a patient with patient-controlled analgesia (PCA) and peripheral nerve block (PNB) developing POUR were 4.2 times and 4.7 times that of a patient without PCA and PNB, respectively. Age, male gender and type of anaesthesia were not found to be significant. Conclusion: In our study population, the incidence of POUR after elective TKA was 24% with major modifiable risk factors being associated with the use of PCA and PNB as post-operative anaesthesia. POUR can have deleterious effects thus alternative post-operative analgesia should be considered.