General anesthesia: to catheterize or not? A prospective randomized controlled study of patients undergoing total knee arthroplasty.

This study was to investigate whether urinary catheterization could be avoided for patients undergoing total knee arthroplasty (TKA) under general anesthesia with saphenous nerve block. 314 patients from a single surgical team were randomized to receive either an indwelling urinary catheter or no urinary catheter before the surgery. The results revealed that the prevalence of postoperative urinary retention (POUR) was quite low in both groups (5.7% vs 6.4%, P=1). Additionally, the prevalence of urinary tract infection was significantly higher in patients using an indwelling catheter (5.1% vs 0.6%, P=0.036). We also identified age, male gender, ASA grade, benign prostatic hypertrophy, intraoperative intravenous fluid and duration of surgery as the risk factors for POUR in these patients.