To Catheterize or Not? in Total Knee Arthroplasty With Combined Spinal-epidural Analgesia

Inclusion Criteria: * Aged 40 years and older, who were scheduled for a primary TKA for end-stage osteoarthritis and those who were willing and able to return for follow-up over at least a 1-month postoperative period. Exclusion Criteria: * Revisions, bilateral procedures, surgical history of urinary system, urinary tract infection and systematical conditions (renal disease, renal failure, chronic renal insufficiency, or an indwelling catheter at the time of surgery) needing intraoperative monitoring urine output.