Pre-Operative Urodynamic Assessment Has Poor Predictive Value for Developing Post-Operative Urinary Retention.

Background: Post-operative urinary retention (POUR) following primary total joint arthroplasty (TJA) has a reported prevalence up to 35%. Risk factors for POUR have included surrogate markers such as the presence or absence of urologic disease. Pre-operative dynamic measurement with post-void residual volumes (PVR) has not been investigated as a tool for assessing POUR risk.

Methods: All male TJA patients underwent an institutional pre-operative screen for POUR, including PVR measurements, patient-derived subjective urinary retention scores, and assessment of urologic disease. The prospectively collected data were retrospectively reviewed. Proportions were evaluated with the chi-squared test, while continuous variables were evaluated by logistic regression analysis. Receiver-operator characteristic curves were utilized to determine the efficacy of using urodynamic variables as a predictor of developing POUR.

Results: Two hundred fifty-two male patients were reviewed who had a mean age of 64.9 years and mean body mass index of 30.8 kg/m. The overall rate of POUR was 5.1%. Patient urinary retention scores were not associated with POUR. Elevated pre-operative PVR (>10 cc) alone and in combination with a history of urologic disease was significantly associated with POUR. However, both had low positive predictive values (10.5% and 18.2%), despite high negative predictive values (99.2% and 97.9%). Utilization of PVR resulted in moderate sensitivity (91.6%) and low specificity (72.1%) with an area under the curve of 0.69.

Conclusion: Urodynamic measurements and patient urinary retention scores, as part of an institutional pre-operative screening protocol, have limited value in determining which patients are at increased risk of POUR. The utility of obtaining these measurements pre-operatively is questionable.