Postoperative urinary retention associated with total hip and total knee arthroplasties.

Urinary retention following total hip and knee arthroplasty is a common problem frequently necessitating either prolonged urethral catheter drainage or intermittent catheterization. The direct relationship of urinary tract instrumentations, procedures, and infections to deep sepsis in total hip replacements is well documented. Pharmacologic therapy to stimulate voiding or augment bladder emptying is thus theoretically preferable to the use of catheterization. Prasozin hydrochloride, an alpha blocker, relaxes the smooth musculature of the posterior urethra and prostrate and has been used to treat urinary obstruction secondary to benign prostatic hypertrophy. A prospective study in 60 male patients showed a statistically significant decrease in postoperative urinary retention with the perioperative administration of prazosin (p less than 0.01). A higher incidence of urinary tract infection was seen in patients who developed urinary retention (3% versus 20%) (p less than 0.01). Uroflowmetry parameters were not predictive of the patient at risk for retention and were unaltered with the administration of prazosin. Prazosin can be an effective adjunct in the prophylaxis of postoperative urinary tract infections and may decrease the potential risk for total joint sepsis.