I am a 65 1/2" inch tall female, so I'm going with medium. My hip resurfacing size was 47. Metal issues are not an issue for me as my surgeon (Pritchett) uses his Synovo Preserve device, which is ceramicized titanium with a highly cross-linked polyethylene sleeve so therefore there are no metal parts to leave metal wear debris. I don't run because I don't like running - it's just not my sport - but I do enjoy walking/hiking and swimming. I have no issues at all with these. I can walk for as many miles as I want now, and I look forward to a great hiking season this year. Plenty of other HR recipients - including those of Dr. P - do run. If I were a runner and wanted to run I could go out for a jog right now without any concern for the hip, but since it's raining I'd rather go to the movies.
blinky's full story is on this website. Mine is as well, and mine is also at hipresurfacingwoman.com.