Urinary Retention After Arthroplasty

Adult patients undergoing knee arthroplasty will be recruited to this study. Participants will be randomized to the ultrasound monitoring group or the symptoms alone group. In the symptoms alone group, urination is monitored by asking at regular intervals about the onset of spontaneous urination and the patient is catheterized only on a symptomatic basis or if spontaneous voiding has not started 10 hours after the spinal anesthesia. Symptoms that indicate catheterization are lower abdominal pain or need to void. In the ultrasound group, urinary retention is monitored according to current practice with an ultrasound scanner and the patient is catheterized if residual urine exceeds 800 ml or if the patient is symptomatic.

The primary outcome variable is the change in IPSS score from the baseline to 3 months after the procedure. The baseline score is evaluated preoperatively.

Inclusion criteria

• elective total knee arthroplasty

Exclusion criteria

• previous surgery for urologic cancer
• fracture as indication for surgery
• lack of co-operation
• untreated urinary retention
• nephrostoma
• general anesthesia