"In a study by another highly regarded open surgeon, Dr. William Catalona, the outcomes of 1,870 consecutive open RRPs (mean patient age of 63) were analyzed (Catalona 1999). Men were considered continent if they “did not require protection to keep outer garments dry.” Overall, of 1,325 men who had >18 month follow-up, 92% recovered urinary continence. This recovery varied slightly by age such that continence rates for men in their 40s, 50s, 60s, and 70s were 92%, 97%, 92%, and 87%, respectively. A recent notable study by Eastham and Scardino analyzed outcomes of 1,577 men after open RP (Eastham 2008). Continence was assessed by patient reported questionnaire or physician interview and defined as answering “no” to the question, “Do you wear any protective material because you leak urine?” Among these patients (mean age 58 years), 79% were continent at 12 months. Litwin et al. investigated the longitudinal recovery of quality of life (back to preoperative baseline) after open RRP in 247 men followed for up to 4 years after surgery (Litwin 2001). At 3, 12, and 30 months after surgery, 21%, 56%, and 63% of men recovered to baseline function and overall about 80% recovered to baseline urinary bother at about 8 months."
So the vast majority of men regain continence within a year.