Three hundred and eighty-eight patients undergoing primary total knee arthroplasty (TKA) (n=228) or total hip arthroplasty (THA) (n=160) with spinal anesthesia were randomized to receive a short-term Foley catheter (n=194) or no catheter (n=194). The primary outcome of interest was the development of postoperative urinary retention (POUR), defined as requiring at least two straight catheterizations or an indwelling urinary catheter placement due to retention of ≥450 mL on bladder scans. Secondary outcomes included the incidence of urinary tract infections (UTIs) within three weeks and the need for at least one straight catheterization. Outcomes were assessed postoperatively and at three weeks. Overall, the study found no significant difference in the rate of POUR between the Foley catheter and no-catheter groups. Additionally, there was no significant difference in secondary outcomes, including UTI rates and the need for straight catheterization. These findings suggest that short-term Foley catheter use does not provide a benefit in reducing POUR risk and may not be necessary in uncomplicated primary TKA and THA cases.