I am 66 and had both hips replaced 2 years ago. I am doing great,no pain. I enjoy jogging and weight lifting with a weighted bar for squats and lunges. My doctor said he could not recommend running. But he knew I had every intention to try it. The way I look at it, at 66 if I had not needed hip replacement and I ran, I would still be putting wear and tear on my hips as I aged. So running with my Zimmer titanium hips should be not be an issue. Actually, I get less tried than before the surgery. However that may be because there is no pain!
Do what feels good!