Postoperative Urinary Catheterization Thresholds of 500 versus 800 ml after Fast-track Total Hip and Knee Arthroplasty A Randomized, Open-label, Controlled Trial

Background: No evidence-based threshold exists for postoperative urinary bladder catheterization. The authors hypothesized that a catheterization threshold of 800 ml was superior to 500 ml in reducing postoperative urinary catheterization and urological complications after fast-track total hip arthroplasty (THA) and total knee arthroplasty (TKA). Methods: This was a randomized, controlled, open-label trial that included patients greater than or equal to 18 yr who underwent THA or TKA in three Danish, fast-track, orthopedic departments. Consenting patients were eligible if they were cooperative and understood Danish. Participants were randomly allocated to a catheterization threshold of 500 or 800 ml, using opaque sealed envelopes. Group assignment was unmasked. Ultrasound bladder scans were performed every second hour until the first voluntary micturition, with subsequent urinary catheterization according to group assignment. The primary outcome was the number of patients catheterized before their first voluntary micturition. Thirty-day telephonic follow-up was on voiding difficulties, urinary tract infections, and readmissions. Results: Of 800 patients allocated, 721 (90%) were included in a per-protocol analysis (20 did not complete the study and 59 were excluded from the analysis). In the 500-ml group, 32.2% received catheterization (114 of 354) compared to 13.4% (49 of 367) in the 800-ml group (relative risk, 0.4; 95% CI, 0.3 to 0.6; P < 0.0001). The authors found no difference between groups in any secondary outcome. Conclusions: In fast-track THA and TKA, a catheterization threshold of 800 ml significantly reduced the need for postoperative urinary catheterization, without increasing urological complications. This large randomized, controlled trial may serve as a basis for evidence-based guidelines on perioperative urinary bladder management.